Download Understanding Nutrition and Your Diet

Confirming Pages
5
Understanding
Nutrition and
Your Diet
What Do You Know About Nutrition?
1. Dietary supplements may be harmful to your health. True or False?
2. Whole-grain bread does not have the same nutritional benefits as
wheat bread. True or False?
3. Most people get enough vitamin D from exposure to the sun.
True or False?
4. Saturated fats are the same thing as trans fats. True or False?
5. Most Americans eat enough fruits and vegetables. True or False?
6. Food allergies can be fatal. True or False?
7. Fruit juice is a good way to meet the dietary recommendations
for the fruit group. True or False?
Check your answers at the end of the chapter.
H
ealthy eating is important from the prenatal period throughout life, in order to p revent
malnourishment and minimize the development of illnesses. Food supports growth and development by providing the body with the nutrients needed for energy, repair of damaged tissue, growth of
new tissue, and regulation of physiological processes. Our food selections also reflect personal, familial,
and cultural traditions. The preparation and serving of food at regular mealtimes and during holiday
gatherings and other special occasions enhance all of the dimensions of health (see the box “Mealtime—A
Chance to Share and Bond”). For example, sharing a meal with fellow parishioners after a religious service
supports the spiritual dimension of health, sharing popcorn at the movies with your friends can enhance
the social dimension of health, and learning about the cuisine of another culture develops the cultural
dimension of health. As you read this chapter, keep in mind this balanced view of food as sustenance and
food as a resource for the dimensions of health.
pay29753_ch05_113-149.indd 113
24/11/11 9:25 AM
Confirming Pages
Discovering Your Spirituality
Mealtime—A Chance to Share and Bond
Food is important to your physical well-being—for energy, growth,
repair, and regulation of your body and its functions. But it’s also
important to the well-being of your spirit. The sharing of food nourishes our spiritual sense of community. This happens through the
type of foods selected, the method of preparation, the uniqueness of
presentation, and the people involved. From a spiritual perspective,
the sharing of food can be a highly satisfying activity.
When food is shared in the company of those who care about us,
we experience a sense of community and well-being. The simple act
of being together and engaging in a familiar practice is reassuring.
Meals that involve family or friends, especially on special occasions
or important holidays, can provide a chance to reconnect and build
relationships.
Food is often at the center of the celebration of special occasions.
Weddings, birthdays, anniversaries, graduations, promotions, retirements,
and funerals take on a special meaning when people come together to
share food and drink. From the first birthday cake, to the retirement dinner, to the lunch provided by neighbors after the funeral of a loved one,
food can help to symbolize and acknowledge these events in our lives.
Food has been part of many religious practices and customs for
centuries. Some foods have symbolic meanings related to major life
Types and Sources of Nutrients
Your body relies on seven nutrients to carry out its
physiological functions: carbohydrates, fats, protein, vitamins, minerals, dietary fiber, and water.* The first three—
carbohydrates, fats, and protein—will be discussed
together because they provide calories .These calories
are either used quickly by our bodies in energy metabolism or stored in the form of glycogen or fat for delayed use
as energy sources. The other nutrients—vitamins, minerals, dietary fiber, and water—are not sources of calories
for the body. However, regardless of their relationship to
calories, all nutrients are essential to human health. The
function of each is discussed later in the chapter.
Carbohydrates
Carbohydrates are various combinations of sugar units,
or saccharides, and are the major energy source for the
body.1
experiences and to ceremonies and religious
rites. Food can take on symbolic and spiritual
meaning, such as bread representing the body
of Christ in the Christian religion. The use of food in spirituality helps
to bring groups together to build a stronger sense of community.
For example, Ramadan, the ninth month of the Islamic calendar, is
considered one of the holiest months of the year in Islam, and from
dawn to sunset Muslims abstain from food. The fast is broken at
sunset when families and friends come together to enjoy traditional
dishes such as fattoush, a salad. In the Jewish religion, the Seder,
a ritual feast celebrated on the first day of Passover, features longheld traditions and customs involving food. Food takes on a symbolic
meaning and is eaten during the retelling of the story of the Exodus
from Egypt and freedom from slavery. In the Christian religion, family and friends celebrate Easter by having a meal together on Easter
Sunday, usually including lamb, which represents Christ and is seen
as a good omen.
Finally, food connects people on a spiritual level by allowing them
to share traditions, religious practices, and beliefs. These customs
help people build a sense of fellowship and can unify them in times of
joy and sorrow.
(monosaccharides and disaccharides) and complex
carbohydrates (polysaccharides).
●
●
●
Monosaccharides—carbohydrates with one saccharide unit. These are the primary source of the body’s
energy. Examples include glucose, found in vegetables, honey, fruits, and syrup; and fructose, found in
fruits and berries.
Disaccharides—carbohydrates with two saccharide
units, one of which is always a glucose unit. Examples
include sucrose, or table sugar; maltose, which is
derived from germinating cereals; and lactose, found
in human and animal milk.
Polysaccharides—carbohydrates with more than two
saccharide units. Polysaccharides include starches
and dietary fiber. Examples are vegetables, breads,
cereals, legumes, and pasta.
Types and Sources of Carbohydrates Carbohydrates
occur in three forms, depending on the number of
saccharide (sugar) units that make up the molecule.
Carbohydrates are divided into two categories: simple
Both simple and complex carbohydrates contain
4 calories per gram, and both are converted into glucose
in digestion. Simple carbohydrates are digested more
quickly because they are composed of fewer saccharide
units than complex carbohydrates. Complex carbohydrates also take longer to digest because they have more
fiber, vitamins, and minerals.
*Since most of our water intake comes from beverages rather than from
food, some nutritionists do not consider water a nutrient, even though it
is essential for life.
How Much Carbohydrate Is Recommended? Each
gram of carbohydrate contains 4 calories. Since the average person requires approximately 2,000 calories per day
114
Understanding Your Health
pay29753_ch05_113-149.indd 114
24/11/11 9:25 AM
Confirming Pages
and about 45–65 percent of our calories come from carbohydrates, it is recommended that approximately 1,200
of our daily calories come from carbohydrates.1 However,
age, gender, and activity level affect the number of calories an individual requires each day; individual energy
needs are discussed later in this chapter.
Simple Sugars: The American Sweet Tooth According
to the U.S. Department of Agriculture (USDA), the
average adult American consumes approximately 22.2
teaspoons of sugar per day while the USDA recommendations are no more than 8 teaspoons per day, a difference
of 335 calories.2 These sugars are usually found in sodas,
candy, and bakery items, which have little nutritional
value. Corn sweetener consumption has decreased since
2003 from 79 pounds to 37.8 pounds per year. However,
sugar consumption has increased to 47.2 pounds per year.
Much of the sugar we consume is hidden; that is,
sugar is a principal product we may overlook in a la rge
number of food items. Foods such as ketchup, salad
dressings, cured meat products, and canned vegetables
and fruits can contain much hidden sugar. Corn syrup,
frequently found in these items, is a highly concentrated
sucrose solution. Whether the sugar is overt or hidden,
the USDA has suggested a limit of 8 teaspoons of sugar
per day for a 2,000-calorie diet, which would be equivalent to 8 ounces of yogurt.
Sugar Substitutes For a number of years, sugar substitutes have been used in a w ide array of beverages,
candy, baked goods, chewing gum, frozen desserts, gelatins and puddings, jams, toppings, and syrups. Among
the most familiar of these are saccharin and aspartame
(NutraSweet), both of which are several hundred times
sweeter than sucrose. Since 1977, saccharin has been
linked to cancer, particularly bladder cancer, and warnings were given about its use until 2000, when Congress
removed this requirement.3 Some of the newer artificial
sweeteners are sorbitol, found in ice cream; acesulfamepotassium (ace K), used in Pepsi ONE; xylitol, found
in some brands of chewing gum; neotame, found in
candy and soft drinks; sucralose (Splenda); and tagatose,
found in Slurpees. These sweeteners can be more than
600 times sweeter than sugar; neotame is 7,000–13,000
times sweeter than sugar. Stevia is an herbal sweetener
made from the leaves of the South American shrub of
the same name. It is 200–300 times sweeter than table
sugar and is sold as a d ietary supplement in the United
States. There has been concern that consumption of
stevia could cause infertility and cancer. Stevia can be
found in soft drinks under the name Truvia (in CocaCola) and Purevia (in Pepsi-Cola). There have been concerns about other artificial sweeteners such as aspartame
and acesulfame-potassium being associated with cancer,
but the USDA has deemed them safe at this point. While
many people use artificial sweeteners as a way to decrease
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 115
caloric intake and to manage weight, studies have shown
that people consuming food and beverages with artificial
sweeteners actually consumed more calories than those
who did not. So sugar substitutes may actually contribute
to weight gain rather than weight loss.4
Fats
Fats (lipids, fatty acids) have been given a bad n ame but
are an important nutrient in our diets. Fats provide a
concentrated form of energy (over double that of carbohydrates—there are 9 c alories per gram consumed versus 4 for carbohydrates and protein). Fats provide a sense
of satiety and keep us from feeling hungry. Because fats
take longer to l eave the stomach than either carbohydrates or proteins do, our stomachs feel full for a longer
period of time, decreasing our appetite. Fats also help to
give our food its pleasing taste, and they serve as carriers
of fat-soluble vitamins A, D, E, and K. Without fat, these
vitamins would quickly pass through the body. Fat insulates the body and helps it retain heat.
Sources of Fat Dietary sources of fat are often difficult to identify. The visible fats in our diet, such as butter, salad oils, and the layer of fat on some cuts of meat,
represent only about 40 percent of the fat we consume.
Most of the fat we eat is “hidden” in food because it is
incorporated into the food during preparation or used to
fry the food or as a sauce.
Types of Fat Every type of dietary fat is made u p of
a combination of three forms of fat (saturated, monounsaturated, and polyunsaturated), based on its chemical
composition (see Figure 5-1). In each of the three forms
of fat, the absence of double bonds (saturated fats) or the
presence of double bonds (monounsaturated and polyunsaturated fats) and the location of the double bonds
within the molecule determine the nature and degree of
restructuring that the body can do i n changing dietary
Key Terms
nutrients Elements in foods that are required for the growth,
repair, and regulation of body processes.
calories Units of heat (energy); specifically, 1 calorie is the
amount of energy needed to raise the temperature of 1 gram
of water by 18C. In common usage, on food labels, and in
this chapter, the term calorie is used to refer to a larger
energy unit, kilocalorie (1,000 calories).
carbohydrates The body’s primary source of energy for
all body functioning; chemical compounds including sugar,
starches, and dietary fibers.
satiety (suh tie uh tee) The feeling of no longer being hungry;
a diminished desire to eat.
Chapter Five
Understanding Nutrition and Your Diet
115
24/11/11 9:26 AM
Confirming Pages
100
Fatty acid composition (% of total)
90
80
70
60
50
40
30
20
10
Pa
Co
c
lm onut
ke oil a
rn
el
oil a
Be
ef
B
fat utte
(ta r
llo
w
Po Palm )
rk
o
fat il a
Ch (lar
ic d)
S ke
St hor n fa
ick te t
ma ning b
rg
ari
ne c
Co
tto
So ns
ft m ee
arg d oil
a
Pe rine d
an
So ut
yb oil
ea
n
Ol oil
ive
o
Su Cor il
nfl n o
ow il
Ca er o
Sa nola il
fflo o
we il
ro
il
0
Solid fats
Saturated fat
Oils
Monounsaturated fat
Polyunsaturated fat
Figure 5-1 Fatty Acid Profiles of Common Fats and Oils
a
Coconut oil, palm kernel oil, and palm oil are called oils because they come from plants. However, they are semi-solid at room temperature due to their high content of shortchain saturated fatty acids. They are considered solid fats for nutritional purposes.
b
Partially hydrogenated vegetable oil shortening, which contains trans fats.
c
Most stick margarines contain partially hydrogenated vegetable oil, a source of trans fats.
d
The primary ingredient in soft margarine with no trans fats is liquid vegetable oil.
Source: U.S. Department of Agriculture, Agricultural Research Service, Nutrient Data Laboratory, USDA National Nutrient Database for Standard Reference, Release 22, 2009,
http://www.ars.usda.gov/ba/bhnrc/ndl, accessed July 19, 2010.
fat into physiology-friendly forms. Today, consumers
need to pay attention to the amount of each type of fat
in dietary fat because of the role that each form plays in
heart disease (see Chapter 10).
Saturated and Trans Fats Not all fats are created
equal. Saturated fats , including those found in animal sources and in vegetable oils to which hydrogen has
been added (hydrogenated), becoming trans-fatty acids ,
need to be carefully limited in a modern healthy diet. The
presence of trans-fatty acids (an altered form of normal
vegetable oil molecules or from meat and dairy products,
having formed naturally by fermentation in the intestinal
tract of animals)5 is associated with changes in the cell
membrane, including those cells lining the artery wall.
This possibly prevents these vessel wall cells from freeing
cholesterol from their surfaces.6 Processing can change
the structure of fat, making it more saturated. As a result,
the oils become semisolid and more stable at room temperature. The term trans describes the chemical makeup
of a fatty acid. Most trans-fatty acids come from hydrogenated oil, which is found in foods such a s stick margarine, peanut butter, and crackers. They are popular in
food manufacturing because they can extend the shelf life
of the food: The oil stays mixed in the food and doesn’t
rise to t he top, and the food doesn’t become too soft at
room temperature. The fast-food industry uses these
fats to fry many foods.7 Additionally, trans-fatty acids
116
are associated with increases in low-density lipoprotein
(LDL), the “bad” cholesterol, without corresponding
increases in high-density lipoprotein (HDL), the “good”
cholesterol8 (see Chapter 10). The amount of trans-fatty
acids in the diet should be limited to 2 grams or less daily.
Trans fats can act like saturated fat, potentially raising
LDL blood cholesterol levels and decreasing HDL cholesterol. This is the reason nutritionists encourage us to use
butter rather than stick margarine. To reduce your intake
of trans fat, make sure you check the labels on foods to see
if they list “partially hydrogenated vegetable oil” as one
of the ingredients. Cakes, cookies, crackers, snack foods,
stick margarine, vegetable shortening, and fried foods are
most likely to contain hydrogenated vegetable oil.
There has been a big push for restaurants and food
manufacturers to d iscontinue using trans fats in their
products, which has resulted in a 70 percent decrease in
the use of trans fats over the past three years. Trans fat
has been called a “ dangerous and unnecessary ingredient” and has been banned for use in restaurants in New
York City. The FDA now requires food manufacturers to
list trans fat on any product that contains more than 0.5
gram of trans fat per serving. However, that means products that boast they contain “no trans fat” can have less
than half a gram of trans fat per serving, and if you eat
multiple servings, you can easily consume more than the
2 grams of trans fat a d ay that is the USDA’s suggested
daily limit. Many food producers are jumping on the
Understanding Your Health
pay29753_ch05_113-149.indd 116
24/11/11 9:26 AM
Confirming Pages
no-trans-fat bandwagon, and you will see more cereals,
chips, crackers, and other foods labeled “No trans fat.”
Monounsaturated Fats Fortunately, the replacement
of saturated fats with monounsaturated and polyunsaturated fats and oils appears to lower blood cholesterol
levels and reduce the risk of heart disease. Vegetable oils
tend to b e low in saturated fats, with the exception of
the tropical oils (coconut, palm, and palm kernel oils).
Monounsaturated fats are found in high quantities in
olive oil, peanut oil, and sesame oil.
Polyunsaturated Fats Polyunsaturated fats are especially prevalent in soybean oil and corn oil. Monounsaturated fats can reduce the harmful low-density lipoproteins
(LDLs). Polyunsaturated fats reduce both LDLs and total
cholesterol. However, polyunsaturated fats also lower the
healthful high-density lipoproteins (HDLs), which is not
a desirable outcome. Omega-3 fatty acids, found in most
varieties of fish, are a type of polyunsaturated fat and
have been associated with decreased risk of heart disease.
Our bodies require omega-3 fatty acids, but we can’t produce them on our own, and therefore we must get them
from the foods we eat. Flax seed, walnuts, and olive oil
are good sources for omega-3 fatty acids. You can also
consume omega-3 fish oil as a dietary supplement.
Tropical Oils Although all cooking oils (and fats such
as butter, lard, margarine, and shortening) have the same
number of calories by weight (9 calories per gram), some
oils contain high percentages of saturated fats. All oils and
fats contain varying percentages of saturated, monounsaturated, and polyunsaturated fats. The tropical oils—coconut,
palm, and palm kernel—contain much higher percentages
of saturated fats than do other cooking oils. Coconut oil is
92 percent saturated fat. Tropical oils can still be found in
some brands of snack foods, crackers, cookies, nondairy
creamers, and breakfast cereals, although they have been
removed from most national brands. Do y ou check for
tropical oils on the ingredients labels of the food you select?
How Much Fat, and What Type, Is Recommended? The
current dietary guidelines recommend that no more than
20–35 percent of our calories come from fat. In addition
it is suggested that people do the following:
●
●
●
Consume less than 10 percent of calories from saturated fatty acids and less than 300 mg per day of
cholesterol, and keep trans-fatty acid consumption
as low as possible, no more than 2 grams per day.
Get most fats from sources of polyunsaturated and
monounsaturated fatty acids, such as fish, nuts, and
vegetable oils.
Make choices that are lean, low-fat, or fat-free when
selecting and preparing meat, poultry, dry beans,
and milk or milk products.
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 117
Food labels are an important source of information about the
type and amount of fats, carbohydrates, and other nutrients
contained in a food.
Cholesterol Cholesterol is a w hite, fatlike substance
found in cells of animal origin. It is not found in any
vegetable product, so products such as peanut butter and
margarine that claim they are cholesterol-free never had
it in the first place. Cholesterol is used to synthesize cell
membranes and also serves as the starting material for
the synthesis of bile acids and sex hormones. Although
we consume cholesterol in our diet, in such f oods as
shrimp and other shellfish, animal fat, and milk, we
don’t need to obtain cholesterol from external sources—
the human liver can synthesize enough of the substance
to meet the body’s needs.
Cholesterol is essential for many of the body’s functions. However, if you have too much cholesterol, it builds
Key Terms
saturated fats Fats that promote cholesterol formation; they
are in solid form at room temperature; primarily animal fats.
trans-fatty acid An altered form of an unsaturated fat
molecule in which the hydrogen atoms on each side of the
double bond(s) are on opposite sides; also called trans fats.
cholesterol A primary form of fat found in the blood; lipid
material manufactured within the body, as well as derived
from dietary sources.
Chapter Five
Understanding Nutrition and Your Diet
117
24/11/11 9:26 AM
Confirming Pages
up in your bloodstream and clogs arteries, putting you
at risk for heart disease, heart attack, and stroke. There
are different kinds of cholesterol. LDL, often referred to
as “bad” cholesterol, builds up on the walls of arteries
to form artery-clogging “plaques” that contribute to t he
development of heart disease and stroke. HDL, or “good”
cholesterol, helps remove excess LDL cholesterol from the
blood and transports it back to the liver, where it can be
eliminated from the body. You want to have lower LDL
(under 130) and higher HDL (over 40), with total cholesterol under 200 (see Chapter 10). Almonds, oatmeal, fish,
soy, and red wine (a limit of one glass daily) help lower
overall cholesterol levels. Whole milk, processed meats,
and foods with trans fats and tropical oils, such a s fast
foods and baked goods, can increase overall cholesterol
levels and should be avoided.
A number of medical conditions can give rise to
high blood cholesterol, such as liver disease, kidney failure, hypothyroidism, and diabetes. Certain medications
(some diuretics, for example) can also raise blood cholesterol, irrespective of diet.
The USDA dietary guidelines recommend that people restrict their dietary intake of cholesterol to 300 mg
or less per day. In addition, no more than 20–35 percent
of your total caloric intake should come from fat, with
most fats being monounsaturated and polyunsaturated.
Low-Fat Foods Low-fat and low-calorie do not mean
the same thing, but often people confuse the two. Fatfree, low-fat, and reduced-fat foods have been popular
for many years, with people thinking they can eat as
much as they want of these foods. This is far from true;
a fat-free or reduced-fat product may have as many if not
more calories per serving than regular products do. For
example, 2 tablespoons of fat-free caramel topping have
103 calories, the same amount as homemade-with-butter
caramel topping; 2 tablespoons of Skippy peanut butter have the same number of calories as 2 t ablespoons
of Skippy reduced-fat peanut butter, 190 calories; and 2
tablespoons of Cool Whip are equal to lite Cool Whip,
25 calories.9
Fatty foods make people feel fuller longer than do
fat-free foods; thus, people tend to eat more of the fatfree foods and so consume more calories. In general, the
lower the fat, the higher the price tag, because the food
industry recognizes that Americans are willing to pa y
more for products labeled reduced-fat and fat-free. However, foods such a s low-fat sour cream, yogurt, or salad
dressings are healthier choices because they have less
saturated fat.
Fat-Free Substitutes Fat-free substitutes such as Z-Trim,
Simplesse, Simple Pleasures, Olestra, and Trailblazer contain no cholesterol and have 80 percent fewer calories
than do similar products made with fat. Although fat-free
substitutes first appeared only in snack foods, today they
118
are found in ice cream, salad dressing, cheese spreads,
yogurt, cakes, pies, and French fries.
The development of Olestra (marketed as Olean), as
an example, required more than 25 years and $200 million on the part of Procter & Gamble, as an array of new
technologies were required. In general, fat-free substitutes
are made through a process called microparticulation, in
which several fatty acids are bonded to a sugar molecule
to create a triglyceride-like molecule that imparts all the
characteristics of fats but is incapable of being enzymatically broken down by the body as are the triglycerides.
In spite of the apparent desirability of the fat-free
technology, concerns have been voiced regarding the
inability of these “nouveau fats” to carry fat-soluble vitamins (vitamins A, D, E, and K) and their interference with
nutrient absorption. Additional concern was raised over
side effects in some people, such as abdominal cramping,
loose stools, anal leakage, and an unpleasant aftertaste.10
Proteins
The word protein derives from the ancient Greek word
proteios, meaning “first importance.” Protein serves
primarily to promote growth and maintenance of body
tissue. However, when caloric intake falls, protein is broken down for glucose. This loss of protein can impede
the growth and repair of tissue. From this, it can be seen
that adequate carbohydrate intake prevents protein from
serving as an energy source.11 Protein also is a primary
component of enzyme and hormone structure; it helps
maintain the acid-base balance of our bodies and serves
as a source of energy (4 calories per gram consumed).
Sources and Types of Proteins Proteins are manufactured in every living cell; they are composed of chains
of amino acids. Amino acids are the “bricks” from
which the body constructs its own protein. Twenty amino
acids are used in various combinations to build the protein required for physiological processes to continue in a
healthy manner.
The human body obtains amino acids from two
sources—by breaking down protein from food (as if to
take a brick wall apart for its bricks) or by manufacturing its own bricks (amino acids) within its cells. The latter process is less than fully successful because only 11 of
the necessary 20 amino acids can be built by the body.
The 9 a mino acids that cannot be built by the body are
called essential amino acids (indispensable amino acids),
because they must be obtained from outside the body
through the protein in food. The 11 amino acids that the
body itself can make are called nonessential amino acids
(dispensable amino acids) because the body does not have
to rely solely on food protein to obtain these bricks.11
In terms of food sources of amino acids, foods can
be classified into one of two types, depending on whether
they can supply the body with the essential amino acids.
Understanding Your Health
pay29753_ch05_113-149.indd 118
24/11/11 9:26 AM
Confirming Pages
Complete protein foods contain all nine essential amino
acids and are of animal origin (milk, meat, cheese, and
eggs). The incomplete protein foods do not contain all the
essential amino acids and are of plant origin (vegetables,
grains, and legumes [peas or beans, including chickpeas
and butter beans]). Vegan vegetarians (discussed later in
the chapter), people with limited access to animal-based
food sources, and those who have significantly limited
their meat, egg, and dairy product consumption, need to
understand how essential amino acids can be obtained
from incomplete protein sources. When even one essential amino acid is missing from the diet, deficiency can
develop.
Soybeans are a good source of protein for vegetarians. Soybeans provide the same high-quality protein
as animal protein. 12Furthermore, soybeans contain no
cholesterol or saturated fat. There has been much debate
about whether consuming foods with soybean can
reduce the risk of heart disease.12 In 1999 the FDA stated
that diets low in saturated fat and cholesterol that include
25 grams of soy protein a day may reduce the risk of heart
disease. The sale of soy foods doubled after that proclamation. However, the research on which that claim was
based has not been replicated, and in February 2006, the
American Heart Association concluded that soy doesn’t
lower cholesterol as much as was originally suggested.
Three long-term government-funded studies currently
are investigating the effects of soy on cholesterol levels
and its role, if any, in the prevention of cancer and heart
disease.13
How Much Protein Is Recommended? The latest recommendations for protein intake are part of a set of standards known as the Dietary Reference Intakes ,or DRIs.
Protein intake recommendations are based on body
weight and activity level. The current DRI for protein is
0.36 gram per pound of body weight per day, based upon
a sedentary lifestyle, and is higher for athletes and those
who are more active. In terms of overall energy intake,
nutritionists recommend that 10–35 percent of our total
caloric intake come from protein.14
Many people think that taking megadoses of vitamins
is healthy; however, it can actually be harmful.
in water) or fat-soluble (capable of being dissolved in
fat or lipid tissue). Water-soluble vitamins include the
B-complex vitamins and vitamin C. Most of the excess
of these water-soluble vitamins is eliminated from the
body during urination. The fat-soluble vitamins are A,
D, E, and K. These vitamins are stored in the body in
the adipose tissue or fat with excessive intake.
Dietary Reference Intakes for Vitamins It is possible
to consume and retain too many fat-soluble vitamins, particularly A and D. All the fat-soluble vitamins, however,
Key Terms
proteins Compounds composed of chains of amino acids;
Vitamins
primary components of muscle and connective tissue.
Vitamins are organic compounds that are required in
small amounts for normal growth, reproduction, and
maintenance of health. Vitamins differ from carbohydrates, fats, and proteins because they do n ot provide
calories or serve as structural elements for our bodies.
Vitamins serve as coenzymes. By facilitating the action
of enzymes, vitamins help initiate a wide variety of body
responses, including energy production, use of minerals,
and growth of healthy tissue.
amino acids The building blocks of protein; can be
Types and Sources of Vitamins Discovered in the
early twentieth century, the 13 essential vitamins can
be classified as water-soluble (capable of being dissolved
enzymes Organic substances that control the rate of
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 119
manufactured by the body or obtained from dietary sources.
Dietary Reference Intakes (DRIs) Measures that refer
to three types of reference values: Estimated Average
Requirement, Recommended Dietary Allowance, and
Tolerable Upper Intake Level.
vitamins Organic compounds that facilitate the action of
enzymes.
physiological reactions but are not altered in the process.
Chapter Five
Understanding Nutrition and Your Diet
119
24/11/11 9:26 AM
Confirming Pages
Table 5.1 Facts About Vitamins and Minerals
Functions in the Body
Selected Food Sources
Adult Daily DRI*
Supports the nervous system, helps form red
blood cells, aids digestion and energy production
Helps produce and maintain new cells, prevents a
form of anemia and neural tube birth defects
Liver, eggs, peas, beans, nuts, tomatoes; smaller
amounts in fruits and meats
Dark green leafy vegetables; legumes; oranges;
bananas; enriched, fortified, and whole-grain
products
Helps maintain the skin and the nervous and
digestive systems, helps the body process protein
and fats
Helps form new red blood cells, helps the body
process nutrients
Helps maintain skin and create energy
Meat, fish, poultry; peanuts; beans; enriched,
fortified, and whole-grain products
Men: 30 mg
Women: 30 mg
Men: 400 mg
Women: 400 mg
UL: 1,000 mg from
supplements
Men: 16 mg
Women: 14 mg
UL: 35 mg
Men: 5 mg
Women: 5 mg
Men: 1.3 mg
Women: 1.1 mg
Men: 1.2 mg
Women: 1.1 mg
Men: 1.3 mg
Women: 1.3 mg
UL: 100 mg
Men: 2.4 mg
Women: 2.4 mg
Men: 90 mg
Women: 75 mg
UL: 2,000 mg
Water-Soluble Vitamins
Biotin
Folate
Niacin
Pantothenic acid
Riboflavin
Thiamine
Vitamin B6
Vitamin B12
Vitamin C
Supports the nervous system, aids in production
of energy from carbohydrates
Helps form enzymes and maintain normal blood
sugar levels, supports the nervous and immune
systems, prevents a type of anemia
Maintains healthy nerve and red blood cells, prevents one type of anemia
Helps form connective tissue, acts as an antioxidant, promotes wound healing and iron absorption
Chicken, beef, potatoes, oats, tomato products,
peas, beans, eggs, broccoli, whole grains
Organ meats, milk, bread products, fortified
cereals
Enriched, fortified, and whole-grain cereals and
other grain products
Fortified cereals, soybeans, meat, poultry, fish,
bananas, carrots, potatoes, nuts
Fortified cereals, meat, fish, poultry, eggs, milk
Citrus fruits, tomatoes, potatoes, cruciferous vegetables, green leafy vegetables, strawberries, bell
peppers, tomato juice
Fat-Soluble Vitamins
Vitamin A
Vitamin D
Aids in vision, bone growth, immunity, reproduction, and tissue repair; maintains healthy skin and
mucous membranes; acts as an antioxidant
Helps the body absorb calcium and phosphorus
and build bone, supports immune function, regulates cell growth
Liver, dairy products, tomatoes, fish, eggs, deep
yellow and orange fruits and vegetables, dark
green vegetables
Fatty fish, eggs, fortified milk products and
cereals
Men: 900 mg
Women: 700 mg
UL: 3,000 mg
Men: 5 mg
Women: 5 mg
UL: 50 mg
200 IU
(Continued)
hold the potential for toxicity if taken in amounts that
far exceed Dietary Reference Intakes (see Table 5.1). Most
toxicity results from the use of supplements by adults or
through excessive food intake of particular sources in
very small children. When toxicity develops, the condition is referred to as hypervitaminosis.
People often think taking megadoses of vitamins such
as vitamin C can be health-enhancing, but the reverse is
true. Taking large doses of vitamin C from a dietary supplement can put a strain on your kidneys, causing kidney
stones and diarrhea. Too much niacin, vitamin B6, and
folate can also be harmful.7
Because water-soluble vitamins dissolve rather
quickly in water, you should be cautious in the preparation of fresh fruits and vegetables. One precaution is
to avoid overcooking fresh vegetables. The longer fresh
120
vegetables are steamed or boiled, the more water-soluble
vitamins will be lost. More vitamins are retained with
microwave cooking and steaming than with boiling
vegetables. Even soaking sliced fresh fruit or vegetables can result in the loss of vitamin C and B-complex
vitamins.
Taking a multivitamin can serve as added protection
to ensure you are getting all of your recommended vitamins daily. To ensure an adequate vitamin intake, do not
rely solely on bottled vitamins sold in grocery stores or
health food stores. The best way is really the simplest and
least expensive way: Eat a variety of foods. Unless there
are special circumstances, such as pregnancy, infancy, or
an existing health problem, usually anyone in our society who eats a r easonably well-rounded diet consumes
appropriate levels of all vitamins.
Understanding Your Health
pay29753_ch05_113-149.indd 120
24/11/11 9:26 AM
Confirming Pages
Table 5.1 Facts About Vitamins and Minerals (Continued)
Functions in the Body
Selected Food Sources
Adult Daily DRI*
Vitamin E
Helps repair body tissues, supports immunity,
acts as an antioxidant
Vitamin K
Promotes normal blood clotting and bone health
Vegetable oils, fortified grains, seeds, nuts,
tomato products, green leafy vegetables,
avocados
Dark green leafy vegetables, cruciferous vegetables, vegetable oils, cheese
Men: 15 mg
Women: 15 mg
UL: 1,000 mg
Men: 120 mg
Women: 90 mg
Men: 1,000 mg
Women: 1,000 mg
UL: 2,500 mg
Men: 8 mg
Women: 18 mg
UL: 45 mg
Men: 420 mg
Women: 320 mg
UL: 350 mg from
supplements
Men: 4,700 mg
Women: 4,700 mg
Minerals (Selected)
Calcium
Forms bone, aids in blood clotting and muscle and
nerve function
Dairy products, calcium-set tofu, canned fish,
dark green vegetables, fortified products
Iron
Helps form red blood cells, enzymes, and proteins;
supports energy production and the immune system; prevents a form of anemia
Maintains normal muscle, nerve, and heart functions; supports immunity; helps the body produce
energy; aids in bone health
Meat, shellfish, poultry, legumes, fortified grain
products, deep green leafy vegetables, pumpkin
seeds
Green leafy vegetables, whole grains, seeds,
nuts, legumes, fish, soybeans, artichokes
Potassium
Aids in nerve transmission and muscle function,
helps regulate blood pressure
Sodium
Maintains body fluid balance and blood pressure,
aids in nerve transmission and muscle function
Zinc
Supports immunity, aids in tissue repair, maintains the senses of taste and smell, aids in reproduction, growth, development
White and sweet potatoes, green leafy vegetables, winter squash, bananas, oranges, dried
fruit, legumes, tomatoes
Processed foods, table salt, soy sauce, and other
condiments; small amounts occur naturally in
foods
Fortified cereals, red meat, poultry, certain seafood, milk, eggs, whole grains, legumes, seeds,
nuts
Magnesium
Men: 1,500 mg
Women: 1,500 mg
UL: 2,300 mg
Men: 8 mg
Women: 18 mg
UL: 40 mg
*For a complete listing of the Dietary Reference Intakes for all age groups and life stages, as well as information on the adverse effects of excessive consumption, visit the
website for the Food and Nutrition Board, Institute of Medicine, National Academies (www.iom.edu/CMS/3788.aspx).
Sources: Food and Nutrition Board, Institute of Medicine of the National Academies. Dietary Reference Intakes, www.iom.edu/CMS/3788.aspx; U.S. Department of Health
and Human Services and U.S. Department of Agriculture. Dietary Guidelines for Americans 2010, www.healthierus.gov/dietaryguidelines; NIH Office of Dietary Supplements,
Vitamin and Mineral Supplement Fact Sheets, http://ods.od.nih.gov/Health_Information/Vitamin_and_Mineral_Supplement_Fact_Sheets.aspx.
Should You Take a Vitamin Supplement? While conducting research to formulate the new dietary guidelines,
the USDA found that most Americans are consuming
too many calories but are not meeting their nutritional
needs. How can this be? We eat too many nutrientdeficient foods such as junk food and not enough nutrient-dense foods (which will be discussed later in this
chapter). The USDA and the American Dietetic Association recommend following the USDA dietary guidelines,
particularly eating 4½ cups of fruits and vegetables a day,
rather than taking supplements to rectify this problem.
Most Americans do not consume this amount of fruit
and vegetables on a daily basis and don’t meet their DRIs.
We discuss the dietary guidelines in a later section.
Some believe that additional vitamin intake will prevent or delay the onset of chronic health conditions such
as cancer and cardiovascular disease. To date there seems
to be no conclusive evidence regarding the effectiveness
of most supplements in chronic disease prevention. That
said, there is at least one well-established success story
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 121
regarding vitamin supplementation: the effectiveness of
folic acid supplementation in ensuring the appropriate
closure of the neural tube during embryonic development, thus preventing the development of spina bifida.15
In spite of widespread awareness of the necessity for folic
acid, however, nearly one-third of women of childbearing
age do not take this B vitamin on a daily basis.
The DRI for folic acid for adults is 300–400 mg
daily; however, for pregnant women it is 600 mg a d ay,
and for lactating women it is 500 mg daily. There has
been some debate about whether folic acid can prevent
cardiovascular disease, cancer, and Alzheimer’s disease.
There still isn’t enough evidence to make these claims.
Key Terms
hypervitaminosis Excessive accumulation of vitamins
within the body; associated with the fat-soluble vitamins.
Chapter Five
Understanding Nutrition and Your Diet
121
24/11/11 9:26 AM
Confirming Pages
Some research suggests that folic acid can accelerate the
spread of cancer in people with precancerous or cancer
cells. Vitamin B12 deficiency is a concern for vegetarians
because this vitamin is primarily obtained from liver,
fish, cheese, and eggs. Anemia, disturbances in walking and balance, a loss of vibration sensation, confusion,
and dementia can be caused by vitamin B12 deficiencies.
The body requires B12 to make the protective coating
surrounding the nerves, and inadequate B12 can expose
nerves to damage. B12 can sometimes be difficult for the
body to absorb. The DRI for vitamin B12 is 2.4 mg daily
and for B6 is 1.3–1.7 mg per day. Vitamin B6 deficiency
can lead to a nemia, fatigue, poor appetite, and diarrhea. Good sources of B6 are meat, liver, cereal, grains,
bananas, and nuts.
Who else might benefit from vitamin supplementation? In the opinion of nutritionists, this group might
include vegans, people with limited milk intake and
limited exposure to sunlight, people with lactose intolerance, and people on a severely restricted weight loss diet.
Children and adolescents are another group that may
benefit from vitamin D su pplements. Physicians have
been increasingly concerned about vitamin D deficiency
owing to reduced outdoor activity and decreased milk
consumption among children and adolescents. Stress, as
well as soft drinks, fiber, and iron in foods, can decrease
calcium absorption, and calcium is best absorbed when
taken in frequent, small amounts and with meals. Vitamin C i mproves the absorption of calcium, as does the
presence of estrogen (so women after menopause are at
increased risk of calcium deficiency).
If you take a v itamin D su pplement, look for vitamin D3 (also called cholecalciferol) instead of vitamin
D2, which is 25 percent less potent. The DRI for vitamin
D has been increased to 6 00 international units (IU)
(higher for individuals over 50 years of age), with 50 mg
or 2,000 IU as the Tolerable Upper Intake Level (UL).
The recommended amount of calcium intake is 1,000 mg
a day (1,200 if you are over 50 years of age).16 Too much
calcium may cause kidney stones and may block absorption of other substances such as antibiotics.
Physicians also recommend supplementation to individual patients because of pregnancy, lactation, smoking,
and malnutrition. People with diabetes, cancer, colitis,
pancreatitis, or other medical conditions may also benefit
from a vitamin supplement. Some physicians recommend
that supplements be taken with food, since they’re really
components of food and help the body metabolize other
food components. The fat-soluble nutrients should be
taken with a l ittle oil or fat to en hance absorption. The
water-soluble nutrients are easily absorbed without food
but may work better when taken with meals. In addition,
some people complain of stomach upset when they take
vitamins on an empty stomach. See the box “Should You
Take a Fish Oil Supplement?” for a discussion of another
dietary supplement.
122
Phytochemicals
Certain physiologically active components are believed
to deactivate carcinogens or function as antioxidants .
Antioxidants are substances that may protect cells
from the damage caused by unstable molecules known
as free radicals, which can lead to c ancer. Antioxidants
may prevent cancer by interacting with and stabilizing
free radicals. A f ew examples of antioxidants are beta
carotene, lycopene, and vitamins C, E, and A. However,
Americans’ number-one source of antioxidants is coffee. Chocolate, green tea, and nuts are other popular
sources of antioxidants for Americans.17 The different
types of phytochemicals include the carotenoids (from
green vegetables), polyphenols (from onions and garlic),
indoles (from cruciferous vegetables), and allyl sulfides
(from garlic, chives, and onions). These phytochemicals
may play an important role in sparking the body to fight
and slow the development of some diseases, such as cancer. At this time, however, the exact mechanisms through
which the various phytochemicals reduce the formation
of cancer cells is not understood. Although it is generally agreed that these foods are important in planning
food selections, no precise recommendations regarding
the amounts of various phytochemical-rich plants have
been made.
Minerals
Nearly 5 p ercent of the body is composed of inorganic
materials, the minerals. Minerals function primarily as
structural elements (in teeth, muscles, hemoglobin, and
thyroid hormones). They are also critical in the regulation of a number of body processes, including fluid balance, nerve impulses, muscle contraction, heart function,
blood clotting, protein synthesis, and red blood cell synthesis. Approximately 21 minerals have been recognized
as being essential for human health.1 Unlike vitamins,
minerals are inorganic and can’t be destroyed by heat or
food processing.
Macronutrients (major minerals) are those minerals
that are seen in relatively high amounts in our body tissues.
Examples of macronutrients are calcium, phosphorus,
sodium, potassium, and magnesium. Examples of micronutrients, minerals seen in relatively small amounts in
body tissues, include zinc, iron, copper, selenium, and
iodine. Although micronutrients (trace elements) are
required only in small quantities, fewer than 20 mg daily of
each, they are still essential. Active, menstruating women
need at least 18 mg of iron daily; however, a well-balanced,
2,000-calorie diet supplies around 12 mg of iron. Eating a
food rich in vitamin C along with iron-rich foods will help
your body efficiently utilize iron. Examples of this might
be eating spaghetti with meat and tomato sauce, meat and
potatoes, hamburger and coleslaw, fruit and iron-fortified
cereal, or fruit with raisins.
Understanding Your Health
pay29753_ch05_113-149.indd 122
24/11/11 9:26 AM
Rev. Confirming Pages
Considering Complementary Care
Should You Take a Fish Oil Supplement?
Everywhere you look, you encounter some individual or group
extolling the wonders of fish oil in lowering incidence of heart
disease; reducing the risk of breast and colon cancer; lowering blood
pressure; acting as an antiaging agent; fighting depression, bipolar
disorder, and schizophrenia; mitigating age-related macular
degeneration contributing to blindness; and reducing the symptoms
and pain associated with arthritis. Are these claims too good to be
true, or should you jump on the fish oil bandwagon?
It is not the fish oil but the important omega-3 fatty acids such
as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)
contained in fish oil that result in these health benefits. We cannot
make omega-3 fatty acids, so we rely on food or external sources for
these fatty acids. The FDA does not have a specific recommended
dosage for fish oil but suggests that an average healthy person
should eat two servings of fish per week or obtain the equivalent
through fish oil or other sources. The FDA further recommends
not exceeding 3 grams of omega-3 fatty acids per day, as higher
doses can increase the risk of bleeding, easy bruising, and nose
bleeds, as fish oil tends to thin the blood. The best sources of fish
oil are salmon, tuna, sardines, and anchovies. If you take a fish oil
supplement, make sure it contains omega-3 fatty acids, as it is the
omega-3, not the fish oil, that produces the health benefits.
Water and Fluids
Water may well be our most essential nutrient, since
without water most people would die from dehydration
effects in less than a week. People could survive for weeks
and even years without some of the essential minerals
and vitamins. More than half the body’s weight comes
from water. Water provides the medium for nutrient
and waste transport and temperature control, and plays
a key role in nearly all of the body’s biochemical reactions. A common indication of inadequate fluid intake is
strained, uncomfortable bowel movements.
Most people seldom think about the importance
of an adequate intake of water and fluids. The average
adult loses about 10 cups of water daily through perspiration, urination, bowel movements, and breathing. Physical activity and heat exposure contribute to water loss
and an increased need for fluids. The Institute of Medicine’s general recommendation for the average woman is
approximately 2.7 liters (91 ounces) of total water (from
all food and beverages) each day, and for the average man
approximately 3.7 liters (125 ounces) daily. Recommendations for fluid intake vary with age, gender, metabolism, weight, and diet.
There are several ways to calculate how much water
intake an individual requires. One simple rule is that
for every pound of body weight, you need about half an
ounce of fluid intake per day. Another method is to base
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 123
Another consideration in taking a fish oil
supplement is to read the labels to ensure quality
and safety. Fish oil can become rancid quickly, and rancid fish oil
has the opposite health benefits, promoting heart disease. Make
sure the fish oil is fortified with antioxidants, especially vitamin E,
which prevents oxidation. There have also been concerns about
fish oil being contaminated with environmental pollutants such as
mercury. Some common side effects in taking fish oil supplements
are fish-flavored belches, upset stomach, nausea, and diarrhea.
Liquid fish oil or a vegetarian alternative may be a better option if
you encounter these side effects.
A vegetarian option is to consume enough alpha-linolenic acid
(ALA), a third type of omega-3 fatty acid, as the body can convert it
into EPA and DHA. ALA is found in dark green leafy vegetables, flax
and hemp seeds, walnuts, and vegetable oils. However, sometimes
the body is not able to convert ALA into EPA and DHA, or the
individual doesn’t consume enough ALA in his or her diet. There are
also vegetarian supplements such as Seven Seas omega-3.
Sources: Fish oil benefits, www.fishoilbenefit.net, May 14, 2010; Making
sense of omega-3 fatty acids, www.drbenkim.com, October 13, 2009.
your fluid need on your caloric intake, using the following formula: 0.034 ounce 3 daily caloric intake 5 daily
fluid requirement in ounces.
About 80 percent of people’s total water intake comes
from drinking water and beverages, including caffeinated beverages, while the other 20 percent is derived
from food. It is recommended that you avoid beverages
that are high in sugar, such as fruit juice, regular sodas,
and flavored coffee drinks. For example, a St arbucks
white chocolate mocha has 400 calories.18
Key Terms
antioxidants Substances that may prevent cancer by
interacting with and stabilizing unstable molecules known
as free radicals.
phytochemicals Physiologically active components of foods
that are believed to deactivate carcinogens and to function
as antioxidants.
trace elements Minerals whose presence in the body
occurs in very small amounts; micronutrient elements.
dehydration Abnormal depletion of fluids from the body;
severe dehydration can be fatal.
Chapter Five
Understanding Nutrition and Your Diet
123
11/30/11 4:43 PM
Confirming Pages
To see if you’re drinking enough fluid, check your
urine. A sma ll amount of dark-colored urine can be an
indication that you are not consuming enough fluid and
need to drink more. Urine that is pale or almost colorless
means you are most likely taking in enough fluids. Of
course, people also obtain needed fluids from fruits, vegetables, fruit and vegetable juices, milk, and noncaffeinated
soft drinks, although these can be high in sugar and calories. However, excessive water consumption by persons
of any age, including forced consumption by infants,
can lead to fa tal brain edema (swelling) and aspiration
pneumonia.19, 20
Fiber
Although not considered a nutrient by definition, fiber is
an important component of sound nutrition. Fiber consists of plant material that is not digested but rather moves
through the digestive tract and out of the body. Beans,
fruits, and vegetables all provide us with dietary fiber.
Fiber can be classified into two large groups on the
basis of water solubility. Insoluble fibers are those that
can absorb water from the intestinal tract. By abs orbing water, the insoluble fibers give the stool bulk and
decrease the time it takes the stool to move through the
digestive tract. In contrast, soluble fiber turns to a “ gel”
within the intestinal tract and in so doing binds to liver
bile, which has cholesterol attached. Thus, soluble fiber
is valuable in removing (or lowering) blood cholesterol
levels. Also, because foods high in soluble fiber are generally low in sugar and saturated fats, fiber may indirectly
contribute to ke eping blood sugar low21 and reduce the
risk of colon cancer associated with diets high in saturated fats, although today this latter contention is being
seriously challenged.22
How much fiber do you need? Women need 25 grams
and men require 38 g rams of fiber each day; however,
most American adults eat only 11 grams per day. Fiber
has many benefits, including helping to curb your appetite and prevent overeating because it is filling, requires
more chewing, stays in the stomach longer, and absorbs
water, adding to t he feeling of fullness. Fiber also helps
to slow the absorption of sugar from the intestines, thus
steadying the blood sugar and slowing down the absorption of fat from the foods you eat. Consuming adequate
amounts of fiber has an important effect of reducing serious medical problems because soluble fiber lowers LDL
cholesterol and protects against cardiovascular disease,
whereas insoluble fiber protects against developing colon
cancer.23 A high-fiber diet has been associated with lower
risk of death from infectious and respiratory diseases
as well.24
In recent years attention has been directed toward
three forms of soluble fiber—oat bran, psyllium (from
the weed plantain), and rice bran—for their ability to
lower blood cholesterol levels and prevent heart disease.25
124
To lower your total cholesterol by 5 or 6 points, daily consumption of oat bran equaling a la rge bowl of oat bran
cold cereal or three or more packs of instant oatmeal
would be necessary. One serving of bran plus one serving of beans each day will also fill more than half your
total daily fiber needs. It is recommended that you eat
fiber from a variety of sources to obtain a good balance
of soluble and insoluble fibers.
The Absorption of Nutrients
When we eat, the food is digested and then absorbed into
and through the walls of the gastrointestinal (GI) tract,
into the bloodstream, and is distributed to the cell sites at
which it will be used for energy, growth, repair, and regulation. Figure 5-2 shows the GI tract and other organs of
the digestive system. In terms of the absorption of nutrients, the first 18 inches of the small intestine are the most
active site for absorption, surpassing the level of activity
in the remainder of the small intestine, the large intestine,
and the stomach. Some portion of the alcohol contained in
alcoholic drinks enters the body through the stomach wall
Salivary glands
Tongue
Trachea (to lungs)
Esophagus
(to stomach)
Liver
Gallbladder
Stomach
Pancreas
Large intestine
(colon)
Small
intestine
Appendix
Rectum
Anus
Figure 5-2 The Digestive System Food moves through the digestive
tract (mouth, esophagus, stomach, large and small intestines, rectum,
anus) as it is changed into substances that can be absorbed into the
bloodstream for distribution to the body. The liver, pancreas, and
gallbladder produce enzymes and other compounds that help digest food.
Source: From Insel, P., Core Concepts in Health, 12e. © 2012 by The McGraw-Hill
Companies, Inc. Reprinted by permission.
Understanding Your Health
pay29753_ch05_113-149.indd 124
24/11/11 9:26 AM
Confirming Pages
(more in women than in men), although most is absorbed
in the small intestine. Water and salts are principally regulated by the walls of the large intestine.
In light of the importance of the small intestine, any
injury or disease in this location could seriously harm
one’s nutritional status by impairing the body’s ability to
obtain nutrients. Gastric bypass surgery involves cutting
away a portion of small intestine to restrict the movement of nutrients into the body. Many nutrients needed
for overall health must then be supplemented, often for
the rest of the person’s life (see Chapter 6).
Planning a Healthy Diet
Several tools, including USDA’s MyPlate and the Dietary
Guidelines for Americans, are available to help you plan
a diet that will provide adequate nutrients, as well as
reducing your risk of developing heart disease, cancer,
and other chronic diseases.26
The USDA Food Guide: MyPlate
The most effective way to take in adequate amounts
of nutrients is to eat a ba lanced diet as outlined by the
USDA’s most current guidelines.27 The latest version of
Dairy
Fruits
Vegetables
Grains
Protein
ChooseMyPlate.gov
Balancing Calories
• Enjoy your food, but eat less.
• Avoid oversized portions.
Foods to Increase
• Make half your plate fruits and vegetables.
• Make at least half your grains whole grains.
• Switch to fat-free or low-fat (1%) milk.
Foods to Reduce
• Compare sodium in foods like soup, bread, and frozen
meals – and choose the foods with lower numbers.
• Drink water instead of sugary drinks.
Figure 5-3 Choose MyPlate.gov The USDA changed the pyramid
icon to a plate to prompt consumers to make healthier choices at meals.
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 125
the USDA food group plan is called MyPlate (see Figure 5-3). The USDA replaced MyPyramid with MyPlate
in June 2011, thinking that a plate is a better visual icon to
prompt Americans to ma ke healthier food choices. The
plate is a familiar and simpler icon to decipher. MyPlate
recommends that fruits and vegetables take up half the
plate (a little more vegetables than fruits), with grains
and proteins on the other half of the plate (more grains
than proteins). See Table 5.2 for specific recommendations based upon gender and age. The new MyPlate also
suggests decreasing portion sizes, consuming at least
half your grains from whole grains, drinking fat-free or
low-fat milk, choosing food lower in sodium, and drinking water instead of sugary drinks. Most Americans do
not follow the MyPyramid recommendations in their
daily food intake, and it is hoped that the MyPlate will
be a better way to encourage people to follow the dietary
guidelines. (Figure 5-4 shows how typical American
diets compare to the recommended intake levels.) To
evaluate and track your food intake and physical activity,
visit MyPlate.gov. The “Rate Your Plate” Personal Assessment at the end of this chapter will also help you evaluate
your current eating habits.
Fifteen percent of Americans are not meeting their
nutritional needs according to t he dietary guidelines.
We will look at the specific recommendations and how
Americans are meeting them.
Fruits MyPlate recommends that almost a q uarter of
your plate be filled with fruit for each meal (half your
plate contains fruits and vegetables). The specific amount
depends upon gender and age (see Table 5.2). The dietary
guidelines suggest eating 2 c ups of fruits per day for a
2,000-calorie/day adult diet. However, only a t hird of
adults eat the recommended number of fruits per day. This
is far below the Healthy People 2010 objective from the
U.S. Department of Health and Human Services of having
75 percent of Americans meeting the daily fruit recommendations. One medium-sized fruit, ½ cup dried fruit,
or 1 cup of fresh, frozen, or canned fruit is equivalent to
1 cup. Orange fruits such as mango, cantaloupe, apricots,
and red or pink grapefruit are sources of vitamin A. Kiwi,
strawberries, guava, papaya, cantaloupe, and citrus fruits
are good sources of vitamin C. Oranges and orange juice
also provide folate. Some good sources for potassium are
bananas, plantains, dried fruits, oranges and orange juice,
cantaloupe and honeydew melons, and tomato products.
For the majority of your fruit intake, it is generally recommended that you consume whole fruits and avoid fruit
Key Terms
fiber Cellulose-based plant material that cannot be digested;
found in cereal, fruits, and vegetables.
Chapter Five
Understanding Nutrition and Your Diet
125
24/11/11 9:26 AM
Confirming Pages
Table 5.2
MyPlate Daily Diet Recommendations, by Age and Gender
How many grain foods are needed daily?
Children
Girls
Boys
Women
Men
How much food from the dairy group is needed daily?
Age
Daily
Recommendation
(ounce equivalents)
Daily Minimum
Amount (ounce
equivalents)
2–3
4–8
9–13
14–18
9–13
14–18
19–30
31–50
511
19–30
31–50
511
3
5
5
6
6
8
6
6
5
8
7
6
1½
2½
3
3
3
4
3
3
3
4
3½
3
Children
Girls
Boys
Women
Men
Age
Daily Recommendation (cups)
2–3
4–8
9–13
14–18
9–13
14–18
19–30
31–50
511
19–30
31–50
511
2
2½
3
3
3
3
3
3
3
3
3
3
How much food from the protein foods group is needed daily?
How many vegetables are needed daily or weekly?
Children
Girls
Boys
Women
Men
Age
Daily Recommendation (cups)
2–3
4–8
9–13
14–18
9–13
14–18
19–30
31–50
511
19–30
31–50
511
1
1½
2
2½
2½
3
2½
2½
2
3
3
2½
Children
Girls
Boys
Women
Men
Children
Girls
Boys
Women
Men
Daily Recommendation (cups)
2–3
4–8
9–13
14–18
9–13
14–18
19–30
31–50
511
19–30
31–50
511
1
1½
1½
1½
1½
2
2
1½
1½
2
2
2
Daily Recommendation
(ounce equivalents)
2–3
4–8
9–13
14–18
9–13
14–18
19–30
31–50
511
19–30
31–50
511
2
4
5
5
5
6½
5½
5
5
6½
6
5½
How much is my allowance for oils?
How much fruit is needed daily?
Age
Age
Age
Children
Girls
Boys
Women
Men
2–3
4–8
9–13
14–18
9–13
14–18
19–30
31–50
511
19–30
31–50
511
Daily Allowance (teaspoons)
3
4
5
5
5
6
6
5
5
7
6
6
(Continued)
juices to ensure adequate fiber and to avoid the high sugar
content associated with fruit juices. The American Cancer
Society indicates that this food group may play an important role in the prevention of certain forms of cancer.28
126
Vegetables MyPlate recommends that over a quarter
of your plate contain vegetables at each meal, with half
the plate being filled with fruits and vegetables. The
specific amount of vegetables depends on gender and
Understanding Your Health
pay29753_ch05_113-149.indd 126
24/11/11 9:26 AM
Confirming Pages
is the recommendation for adults following a 2,000calorie diet. Americans fall short in this category as
well, with only 27 percent meeting this recommendation. The Healthy People 2010 objective was for 50
percent of Americans to m eet this recommendation.
As with the fruit group, the important function of this
group is to provide vitamins A and C, complex carbohydrates, and fiber. Because Americans tend to eat only
a few vegetables, such as potatoes, corn, and carrots, the
new guidelines give specific recommendations about
the types of vegetable. One general rule is to “eat your
colors,” meaning you should consume a variety of vegetables over the course of a w eek. The USDA recommends the following:
Table 5.2 MyPlate Daily Diet
Recommendations, by Age and Gender (Continued)
How many empty calories can I have?
Age
Children
Girls
2–3
4–8
9–13
Boys
14–18
9–13
Women
14–18
19–30
Men
31–50
511
19–30
Total Daily Calorie
Needs
Daily Limit for
Empty Calories
1000
1200–1400
135
120
31–50
511
1800
1800
120
160
1600
2200
160
265
1800
1600
2400
160
120
330
1600
2200
2000
260
265
260
Dark green vegetables (such as broccoli and
spinach)—3 cups/week
Red and orange vegetables (such as carrots,
tomatoes, and sweet potatoes)—2 cups/week
Beans and peas (such as soy, kidney, lentil, and pinto
beans)—3 cups/week
Starchy vegetables (such as corn, potatoes, and green
peas)—3 cups/week
Other vegetables (such as cauliflower, asparagus, and
celery)—6½ cups/week
●
●
●
●
●
age (see Table 5.2). Also, MyPlate includes red vegetables such a s red peppers and tomatoes, making a “red
and orange vegetable” subcategory of recommended
intake. Two and one-half cups of vegetables per day
Again, avoid drinking vegetable juices as a wa y of
meeting these requirements because they can be high
Usual intake as a percent of goal or limit
Eat more of these:
Whole grains
Vegetables
Fruits
Dairy
Seafood
Oils
GOAL
15%
59%
42%
52%
44%
61%
Fiber
Potassium
Vitamin D
Calcium
40%
56%
28%
75%
LIMIT
Eat less of these:
Calories from SoFAS*
Refined grains
Sodium
Saturated fat
280%
200%
149%
110%
0%
50%
100%
150%
200%
250%
300%
Percent of goal or limit
Figure 5-4 How Do Typical American Diets Compare to Recommended Intake Levels or Limits?
* SoFAS = Solid fats and added sugars.
Source: Based on data from U.S. Department of Agriculture, Agricultural Research Service, and U.S. Department of Health and Human Services, Centers for Disease Control
and Prevention, What we eat in America, NHANES 2001–2004 or 2005–2006.
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 127
Chapter Five
Understanding Nutrition and Your Diet
127
24/11/11 9:26 AM
Confirming Pages
Table 5.3 USDA Food Guide at Six Different Calorie Levels
Daily Amount of Food from Each Group (vegetable subgroup amounts are per week)
Calorie Level
Food Group
Fruits
Vegetables
Dark green
Red and orange
Beans and peas
Starchy
Other
Grains
Whole grains
Other grains
Protein
Dairy
Oils
Discretionary
calorie allowance
1,200
1,600
2,000
2,400
2,800
3,200
Food group amounts shown in cup (c) or ounce-equivalents (oz-eq), with number of servings (srv) in
parentheses when it differs from the other units. Oils are shown in grams (g).
1c
(2 srv)
1.5 c
(3 srv)
1.5 c/wk
1 c/wk
1 c/wk
2.5 c/wk
4.5 c/wk
4 oz-eq
2
2
3 oz-eq
2c
17 g
171
1.5 c
(3 srv)
2c
(4 srv)
2 c/wk
1.5 c/wk
2.5 c/wk
2.5 c/wk
5.5 c/wk
5 oz-eq
3
2.5
5 oz-eq
3c
22 g
182
2c
(4 srv)
2.5 c
(5 srv)
3 c/wk
2 c/wk
3 c/wk
3 c/wk
6.5 c/wk
6 oz-eq
3
3
5.5 oz-eq
3c
27 g
267
2c
(4 srv)
3c
(6 srv)
3 c/wk
2 c/wk
3 c/wk
6 c/wk
7 c/wk
8 oz-eq
4
4
6.5 oz-eq
3c
31 g
362
2.5 c
(5 srv)
3.5 c
(7 srv)
3 c/wk
2.5 c/wk
3.5 c/wk
7 c/wk
8.5 c/wk
10 oz-eq
5
5
7 oz-eq
3c
36 g
426
2.5 c
(5 srv)
4c
(8 srv)
3 c/wk
2.5 c/wk
3.5 c/wk
9 c/wk
10 c/wk
10 oz-eq
5
5
7 oz-eq
3c
51 g
648
Source: U.S. Department of Health and Human Services and U.S. Department of Agriculture. Dietary Guidelines for Americans, 2010, www.healthierus.gov/dietaryguidelines.
in salt and sugar and don’t provide the fiber intake that
whole vegetables do. Cruciferous vegetables ,such a s
broccoli, cabbage, brussels sprouts, and cauliflower, may
be particularly helpful in the prevention of certain forms
of cancer.28
that children 2–3 years old should consume 2 cups per
day of fat-free or low-fat milk, or equivalent milk products, whereas children 4–8 years of age should consume
2½ cups per day of fat-free or low-fat milk, or equivalent
dairy products. Milk, cheese, pudding, yogurt, and ice
Dairy MyPlate has changed the “milk and milk products” category to t he “dairy” category to i nclude foods
such as yogurt and cheese. MyPlate recommends consuming 3 cups of fat-free or low-fat milk each day, or its
equivalent in another dairy product. The good news is
that the consumption of whole milk is decreasing; however, chocolate milk is rising in popularity. Consumption rates for fat-free, 1 percent, and 2 percent reduced-fat
milk are holding steady, but it was hoped that more people would opt for either the low-fat or fat-free options,
as 2 p ercent milk contains almost as much fat as whole
milk. Overall, Americans are not getting 3 cups of milk
or its equivalent per day as recommended by the dietary
guidelines.
Dairy consumption has been associated with higher
bone density and can help fight osteoporosis.29 Calcium
and high-quality protein, required for bone and tooth
development, are two primary nutritional benefits provided by this food group. The guidelines further suggest
MyPlate recommends that half of all grain servings come from
whole grains. Because whole grains can’t always be identified
by color, it is important to check food labels for whole-grain
content.
128
Understanding Your Health
pay29753_ch05_113-149.indd 128
24/11/11 9:26 AM
Confirming Pages
cream are included in this food group. For individuals
who are lactose-intolerant (lactose upsets their intestines) or are vegan (vegetarians who don’t consume any
animal products, including dairy products), soybeans,
tofu, spinach, kale, okra, beet greens, and oatmeal are
good alternative sources of calcium.
Protein MyPlate changed the “meat, poultry, fish, eggs,
dry beans and nuts” category to simply the “protein” category to encapsulate all of these foods. Our need for selections from this protein-rich group is based on our daily
need for protein, iron, and the B vitamins. Meats include
all red meat (beef, pork, and game), fish, and poultry. It
is strongly recommended that we choose lean meats and
low-fat or fat-free foods in this group. It is further recommended that we increase the amount and variety of
seafood consumed and eat seafood instead of meat and
poultry. Meat substitutes include dry beans, eggs, tofu,
peanut butter, nuts, and seeds. The average American
eats 120 pounds of meat, poultry, and seafood a year, with
beef being the most consumed in this food group and fish
the least. MyPlate recommends that adults eat 5–6 ounces
of protein foods each day. One ounce is equivalent to
●
●
●
●
●
●
1 ounce cooked lean meat, poultry, or fish
1 egg
¼ cup cooked dry beans
¼ cup tofu
1 tablespoon peanut butter
½ ounce nuts or seeds
The fat content of meat varies considerably. Some
forms of meat are only 1 percent fat, whereas others may
be as high as 40 percent fat. Poultry and fish are generally significantly lower in overall fat than are red meats.
Interestingly, the higher the grade of red meat, the more
fat is marbled throughout the muscle fiber. People may
find that higher-grade steak usually tastes better, but that
is because of its higher fat content.
Meats are generally excellent sources of iron. Iron is
present in much greater amounts in red meats and organ
meats (liver, kidney, and heart) than in poultry and fish.
Iron plays a critical role in hemoglobin synthesis in red
blood cells and thus is an important contributor to physical fitness (see Chapter 4) and overall cardiovascular
health (see Chapter 10). However, meat and fish should
be fresh, stored appropriately, and cooked adequately to
reduce the likelihood of serious foodborne illnesses. This
will be discussed later in this chapter.
Grains Bread, cereal, rice, and pasta are referred to as the
“grain group” in the MyPlate icon. Rates of consumption
in this food group are on the rise, as we now eat 25 percent more grains than Americans did in 1970. Corn flour,
starch, and grits are the main grains for which consumption has increased, while the numbers have remained
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 129
steady for oats. There is a particular emphasis on consuming at least half your grains from whole grains. Whole
grains can reduce the risk of chronic disease and help with
weight maintenance.
Whole grains consist of the entire grain seed, or the
kernel, and can’t be identified by the color of the food.
The FDA requires that food contain 51 percent or more
whole-grain ingredients by weight and be low-fat in
order to be called “whole grain.” On food labels, “whole
grain” should be the first ingredient listed. Avoid refined
grains because the grain-refining process typically
removes most of the bran and some of the germ, resulting in the loss of dietary fiber, minerals, vitamins, and
other important nutrients. Wheat flour, enriched flour,
and degerminated cornmeal are not whole grains.
Reading and understanding what labels mean is
important when you are trying to m eet your wholegrain requirements. Optimally, you want the label to say
“100% whole grain,” meaning there is no refined flour
in the food. If it says “Made with whole grain,” then it
has some whole grain but you don’t know how much. “A
good source of whole grain” indicates that the food may
have as little as 8 grams of whole grain per serving, and
“An excellent source of whole grain” means as little as 16
grams per serving. “Multigrain” is a m ixture of grains
that is mostly refined grain with some whole grains sprinkled in. Some products are labeled enriched ,meaning
that some of the nutritional elements that were removed
during processing are returned to t he food; however,
only three B vitamins (thiamine, niacin, riboflavin) and
iron are replaced.
The food industry has risen to the challenge of providing nutritious whole-grain foods with improved taste
and texture. For example, ConAgra spent millions of
dollars to develop “white wheat” made from a naturally
occurring albino variety of flour. It has 3½ times more
dietary fiber, 11 times more vitamin E, 5 t imes more
magnesium, and 4 times more niacin than does refined,
unenriched wheat flour. It also tastes milder and sweeter
than most whole grains do. It combines the best of both
worlds—the nutrition of whole wheat and the taste of
white flour.30
For a 2,000-calorie diet, MyPlate recommends 6 ounces of grains daily, with at least 3 o unces coming from
Key Terms
cruciferous vegetables Vegetables, such as broccoli,
whose plants have flowers with four leaves in the pattern of
a cross.
enriched Foods that have been resupplied with some of the
nutritional elements (B vitamins and iron) removed during
processing.
Chapter Five
Understanding Nutrition and Your Diet
129
24/11/11 9:26 AM
Confirming Pages
whole grains. Specific recommendations vary depending
on gender and age (see Table 5.2). One ounce is equivalent to
●
●
●
1 slice bread
1 cup dry cereal
½ cup cooked rice, pasta, cereal
The nutritional benefit from the breads, cereals, rice,
and pasta group lies in its contribution of B-complex
vitamins and energy from complex carbohydrates. Some
nutritionists believe that foods from this group promote protein intake, since many of them are prepared
as complete-protein foods—for example, macaroni and
cheese, cereal and milk, and bread and meat sandwiches.
Oils The USDA defines oils as fats that are liquid at
room temperature, such as vegetable oils used in cooking. Oils come from many different plants and from
fish. Some common oils are canola oil, corn oil, cottonseed oil, olive oil, safflower oil, soybean oil, and
sunflower oil. Canola and olive oil are preferred over
other types of oils. Some foods, such a s nuts, olives,
fish, and avocados, are naturally high in oils. Foods that
are mainly oil include mayonnaise, salad dressings, and
soft margarine with no trans fats. A limit of 24 grams,
or 6 teaspoons, of oils is the daily recommendation,
although this can vary by gender and age (see Table 5.2).
One teaspoon is equal to
●
●
●
●
1 teaspoon margarine
1 tablespoon low-fat mayonnaise
2 tablespoons light salad dressing
1 teaspoon vegetable oil
Empty Calories Where do such i tems as beer, butter,
candy, sodas, cookies, corn chips, and pastries fit into
your diet? Most of these items contribute relatively little
to healthful nutrition; they provide additional calories,
generally from sucrose and significant amounts of salt
and fat. Fats, salt, sugar, and alcohol are referred to a s
“empty calories” and are limited to 120–330 calories a
day by the MyPlate food guide depending on gender and
age (see Table 5.2). As described earlier in this chapter,
the recommended total daily fat intake should be 20–35
percent of total calories, with most fats coming from
sources of polyunsaturated and monounsaturated fatty
acids. Less than 10 percent of total calories should be
from saturated fats, and less than 300 mg per day should
come from cholesterol. Trans-fatty acid consumption
should be kept to 2 grams or less daily.
The USDA also suggests that we choose and prepare
foods and beverages with little added sugars or caloric
sweeteners. The new food guide recommends no more
than 8 teaspoons of added sugars per day, which is equivalent to ½ ounce of jelly beans or an 8-ounce glass of
130
The Dietary Guidelines for Americans recommend that we
increase our intake of fruits, vegetables, whole grains, and fatfree or low-fat dairy products. Fruit can be easily incorporated
into the daily diet as part of a meal or as a snack.
lemonade. Eating too much sugar is thought to be a major
contributor to the increase in obesity in Americans.
Dietary Guidelines for Americans 2010
The Dietary Guidelines for Americans are science-based
and summarize the most current information regarding
nutrition, health, physical activity, and food safety. The
goal of these guidelines is to lower the risk of chronic disease and promote health through diet and physical activity. Together, these guidelines encourage Americans to
take in fewer calories, make wiser food choices, and be
more physically active. The key recommendations focus
on increasing consumption of nutrient-dense food and
fruits and vegetables, exercising regularly, decreasing
portion sizes, and decreasing consumption of sodium,
trans fat, saturated fatty acids, dietary cholesterol, sugar,
refined grains, and alcohol. We will discuss these recommendations in the next section along with guidelines for
food safety and special populations.
Focus on Nutrient Density Many Americans consume too many calories and too much saturated and
trans fat, cholesterol, added sugar, and sodium. At the
same time, many people do not meet the recommended
intakes for fiber and a number of vitamins and minerals.
Understanding Your Health
pay29753_ch05_113-149.indd 130
24/11/11 9:26 AM
Confirming Pages
Therefore, people should choose mostly nutrient-dense
foods ,which provide substantial amounts of vitamins
and minerals and comparatively few calories. Junk foods
typically are not nutrient-dense because they are high in
sugar and saturated and trans fat, high in calories, and
low in vitamins and minerals. Choosing nutrient-dense
foods can be especially challenging when eating out.
Following the recommendations in the MyPlate plan
can help you choose nutrient-dense foods. In general,
Americans are advised to consume more dark green and
red and orange vegetables; more legumes, fruits, and whole
grains; low-fat milk and dairy products; and more seafood.
Physical Activity Of course, part of managing your
weight in a healthy manner includes physical activity.
The Dietary Guidelines for Americans emphasize the
important role that physical activity plays in our lives.
It is proposed that adult Americans engage in at least
2 hours and 30 minutes of moderate-intensity aerobic
physical activity spread over three days a week. This is
in addition to the usual activities of daily life at work
or home on most days of the week to reduce the risk of
chronic disease. It is further recommended that adults
engage in strength training activities such a s sit-ups,
push-ups and weight lifting two times a week. Children
and adolescents are to enga ge in one hour or more of
moderate- to vigorous-intensity physical activity every
day, including strengthening activities such as climbing and jumping at least three times a w eek. Children
younger than 5 are recommended to be active each day.
Seventy-seven percent of Americans don’t meet the
USDA’s recommendations for physical activity.
Weight Management The Dietary Guidelines for Americans define weight management as meaning “to ma intain body weight in a healthy range, balance calories from
foods and beverages with calories expended, and to prevent gradual weight gain over time, make small decreases
in food and beverage calories and increase physical activity.” The dietary guidelines were designed with the goal of
weight management in mind, and the recommendations
for the different food groups were developed to reach this
goal. However, most Americans don’t know how many
calories they should consume each day to maintain their
weight, making it difficult to ach ieve this goal. Chapter
6 will go into further detail on how to identify a healthy
weight and manage your weight effectively.
Food Groups to Encourage: Fruits, Vegetables, Dairy,
and Seafood Americans are advised to consume more
fiber-rich whole grains, fruits and vegetables, seafood,
and dairy products. Specifically, it is suggested that we
consume 3–6 ounce-equivalents of whole-grain products
per day, with the rest of the recommended grains coming from enriched or whole-grain products. In general,
at least half the grains should come from whole grains.
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 131
Americans are also encouraged to choose a variety of
fruits and vegetables, selecting from all four vegetable
subgroups: dark green, red, orange, and starchy vegetables and legumes. Drinking 3 cups of fat-free or low-fat
milk or the equivalent per day is also encouraged, especially because milk consumption has been decreasing
over the past 30 years. Americans are further encouraged
to drink water instead of sugary drinks. There is also a
push to eat seafood in place of meat and poultry.
Foods to Limit: Fats, Sugars, Sodium, and Alcohol
Choose Your Fats Wisely According to t he USDA, we
should limit our total fat intake to 20–35 percent of calories,
with most fat calories coming from polyunsaturated and
monounsaturated fatty acids. However, 34 percent of calories Americans consume come from fat intake. Less than
10 percent of our calories should come from saturated fatty
acids, keeping our consumption of trans-fatty acids as low
as possible. Also, we need to limit our cholesterol intake to
less than 300 mg/day, getting our protein from low-fat, fatfree, or lean meat, poultry, dairy, and bean products.
Sugar Consumption The Dietary Guidelines for Americans suggest that we choose and prepare foods and beverages with little added sugar or noncaloric sweeteners.
Most added sugar comes from soft drinks; energy, fruit,
and sports drinks; desserts; and candy. For example,
a regular 12-ounce soft drink contains 8 te aspoons of
sugar. The dietary guidelines specifically focus on reducing Americans’ consumption of sugary beverages for this
reason. There is a f urther recommendation to de crease
the amount of added sugars in foods. It is estimated that
Americans consume 400 calories worth of added sugars
daily. Added sugars have been associated with higher risk
of obesity, heart disease, diabetes, and gout.31 Shopping for
foods that limit sugar can be a challenge, however; see the
box “Does Watching Television Influence Your Eating?”
Sodium Intake The USDA guidelines recommend
limiting sodium intake to less than 2,300 mg daily, and
for Americans over 51, less than 1,500 mg daily; however,
the average American consumes 3,400 mg d aily (see
Figure 5-5). Most of our salt intake comes from processed or prepared foods. Many people are unaware
of the high sodium content in prepared foods, sauces,
soups, and canned foods, and so reading the labels for
ingredients is extremely important. You might be surprised by some of the foods that contain salt—cookies,
Key Terms
nutrient-dense foods Foods that provide substantial
amounts of vitamins and minerals and comparatively few
calories.
Chapter Five
Understanding Nutrition and Your Diet
131
24/11/11 9:26 AM
Confirming Pages
Building Media Literacy Skills
Does Watching Television Influence Your Eating?
Does seeing a television advertisement for a juicy, mouth-watering
Steak and Shake burger make you hungry? Does a Dove chocolate
waterfall cascading down the television screen make you salivate?
Advertisers hope so and are spending over $10 billion on food and
beverage television ads each year, with the lowest amount of money
being spent on advertising fruits, vegetables, and milk. Most of these
ads are targeted toward children and adolescents, who view one food
ad every five minutes of television screen time. Eighty-nine percent of
these ads are for products that are high in sugar, fat, and/or sodium.
Children as young as 2 years of age begin asking their parents to buy
certain food items seen on television; this is known in the advertising
industry as “pestering power” or “nag power.” Most of these requests
are for cereal, soft drinks, cookies, and candy, and parents comply
with their children’s requests 50 percent of the time. The least nutritious, high-sugar cereals are the most heavily marketed to children.
Studies have shown that people do eat more after watching television food ads, regardless of how hungry they reported they were
at the time. One study found that children ate 45 percent more after
seeing a television food ad, compared to those who didn’t view one,
potentially contributing to a weight gain of 10
pounds per year. The ads don’t show viewers the
whole picture, such as caloric count or the fat, sodium, and sugar
content of these foods. Nor do they tell viewers that the more people
see these ads, the more they eat and the more they weigh.
So what is the answer? It is very difficult if not impossible to avoid
these ads as they bombard us constantly. Do you think there should
be regulation for food ads, such as requiring them to list the nutritional information for these foods? Should there be an equal number
of ads for fruits, vegetables, and dairy products? One thing that we
as consumers can do is educate ourselves about the nutritional information of these foods—that is, be more informed viewers and look
at the ads with a more realistic and knowledgeable perspective.
Sources: Approximately how much money is spent each year marketing food
products to children? Purdue Extension, March 16, 2010; Story M, French S,
Food advertising and marketing directed at children and adolescents in the
US, International Journal of Behavior, Nutrition, and Physical Activity, 5, 1,
2004; Taylor J, Are fast-food advertisers playing you? WebMD, March 20,
2011; Kids’ cereals pour on the sugar and sodium,
USA Today, October 26, 2009.
5,000
Milligrams per day
4,000
3,000
2,300 mga
2,000
1,500 mgb
1,000
0
2–5
6–11
12–19
20–29 30–39 40–49
Age (years)
Males
50–59
60–69
>70
Females
Figure 5-5 Estimated Mean Daily Sodium Intake, by Age-Gender Group, NHANES 2005–2006
a
b
2,300 mg/day is the Tolerable Upper Level (UL) for sodium intake in adults set by the Institute of Medicine (IOM). For children younger than age 14 years, the UL is less than 2,300 mg/day.
1,500 mg/day is the Adequate Intake (AI) for Individuals ages 9 years and older.
Source: U.S. Department of Agriculture, Agricultural Research Service, and U.S. Department of Health and Human Services, Centers for Disease Control and Prevention,
What we eat In America, NHANES 2005–2006, http://www.ars.usda.gov/Services/docs.htm?docid513793, accessed August 11, 2010.
bread, salad dressings, soft drinks, and cereal. Too much
sodium is linked to hypertension, and about 30 percent
of Americans have sodium-sensitive high blood pressure, which can lead to heart attack or stroke. A st udy
132
showed that a low-sodium diet reduced the risk of cardiovascular disease by 25–30 percent.32 It is estimated
that about 150,000 deaths each year are caused by consumption of too much salt. For this reason salt has been
Understanding Your Health
pay29753_ch05_113-149.indd 132
24/11/11 9:26 AM
Confirming Pages
referred to as the “silent killer,” and the USDA labeled salt
as “public enemy No. 1.” The Institute of Medicine issued
a report in 2010 urging the government to reduce the
maximum amount of sodium that manufacturers and
restaurants can add to foods and beverages.33 For example, the sodium content in McDonald’s Big Mac is 1,040
mg; in Panera’s broccoli cheddar soup, 1,020 mg; and
in Olive Garden’s spaghetti and meatballs, 2,180 mg.33
Some companies are already acting in anticipation of this
possible FDA regulation. Subway decreased its sodium
content by 28 percent in its “fresh fit” sandwich line, following the lead of others who have already cut sodium
in their products, such as PepsiCo, ConAgra, Del Monte,
General Mills, Kraft, Heinz, Mars, Starbucks, and
Campbell. Perhaps sodium will go the way of trans fat in
being severely reduced in Americans’ diet if the food and
beverage industry continues the trend of decreasing the
sodium in its products.
Alcohol Consumption The USDA states that “if alcohol
is consumed, it should be consumed in moderation—up
to one drink per day for women and two drinks per day
for men—and only by adults of legal drinking age.” One
drink is defined as either 12 fluid ounces of regular beer,
5 fluid ounces of wine, or 1½ fluid ounces of 80-proof
distilled spirits. Because alcoholic beverages tend to contribute calories but little nutrition, they are counterproductive to taking in sufficient nutrients while not going
over the daily caloric allotment. However, there are some
indications that moderate alcohol consumption, such as
having a glass of red wine each day, decreases the risk of
coronary heart disease.
Food Safety Food safety has become an increasing
concern with the numerous foodborne pathogens showing up in peanuts, seafood, meat, eggs, vegetables, and
even dog f ood. The Dietary Guidelines for Americans
suggest commonsense safety measures, such a s making
sure your hands and work surfaces are clean before you
prepare food. Food should be cooked or chilled at appropriate temperatures (see the section “Food Safety” on
page 141). It is further suggested that you not wash meat
or poultry prior to preparing them, which is the opposite of what has been advised in the past. Avoid unpasteurized juices, milk, and milk products; raw or partially
cooked eggs, or foods containing raw eggs; undercooked
meat and poultry; and raw sprouts. This will be discussed in more detail in the food safety section later in
this chapter.
Recommendations for Special Populations There
are also some special recommendations for specific
population groups. For people over 50, consuming vitamin B12 in its crystalline form (such as fortified foods or
supplements) is recommended. Women of childbearing
age need to eat iron-rich plant food or iron-fortified food
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 133
with an enhancer for iron absorption, such a s vitaminC-rich foods. Taking in adequate amounts of folic acid
daily from fortified foods or supplements is important
for pregnant women and women who may become pregnant. Pregnant or breast-feeding women are further recommended to consume 8–12 ounces of seafood per week,
limiting tuna and abstaining from tilefish, shark, swordfish, and mackerel due to h igh mercury content. Older
adults, people with dark skin, and those not exposed to
enough sunlight need to consume extra vitamin D from
vitamin-D-fortified foods or supplements.
Dietary modifications may also be recommended for
athletes and other active individuals.
Additional Eating Plans
and Recommendations
Other eating plans are consistent with the Dietary
Guidelines for Americans and appropriate for different
groups. This section describes the DASH diet, introduces
different types of vegetarian diets, and provides nutritional guidelines for older adults. The box “Diverse Food
Pyramids” describes food group plans based on different
ethnic dietary patterns.
Dietary Approaches to Stop Hypertension (DASH) The
DASH diet is not a weight loss program but an example of
how to eat in accordance with the Dietary Guidelines for
Americans. The DASH diet is constructed across a range
of calorie levels to meet the needs of various age and gender groups. Originally developed to study the effects of an
eating pattern on the prevention and treatment of hypertension, DASH is a ba lanced eating plan consistent with
the USDA’s dietary guidelines and similar to the mediterranean diet. You can view examples of the DASH program on the National Institutes of Health website at www.
nhlbi.nih.gov/health/public/heart/hbp/dash. Table 5.4 also
shows how the DASH diet varies by caloric intake requirements. A 25-year study of 88,000 women showed that those
who followed the DASH diet were 24 percent less likely to
have a stroke than were those who didn’t follow it .
Vegetarian Diets
For some, vegetarianism is a way of eating, and for others, it is a way of life. In the sections that follow, various
forms of vegetarianism will be addressed. The MyPlate
food guide described earlier in this chapter can be used
as a guide for all types of vegetarian diets as well.
A vegetarian diet relies on plant sources for most
of the nutrients the body needs. Studies show that vegetarians who eat a balanced diet don’t seem to have any
more iron-deficiency problems than do meat eaters.
Although the iron in plant food is not as well absorbed as
the iron in animal food is, vegetarians tend to eat more
iron-containing foods and more vitamin C foods, which
Chapter Five
Understanding Nutrition and Your Diet
133
24/11/11 9:26 AM
Confirming Pages
Learning from Our Diversity
Diverse Food Pyramids
Besides MyPlate, discussed earlier in this chapter, other food pyramids
exist. The Mediterranean food pyramid emphasizes fruits, beans,
legumes, nuts, vegetables, whole grains, and small amounts of meat.
In fact, the latest version of the USDA pyramid and dietary guidelines
is in keeping with what had already been suggested by the Mediterranean food pyramid—for example, using more olive oil; limiting consumption of alcohol; eating more whole grains, fruits, and vegetables;
choosing lean meat; eating fish and shellfish; and exercising daily.
The Asian food pyramid limits meat consumption even more by
recommending consumption of meat on a monthly basis and daily
consumption of fish, shellfish, and dairy products. The Asian diet,
like the Mediterranean diet, encourages daily intake of fruit, legumes,
vegetables, and whole grains. In addition, the Asian diet includes rice
and noodles and suggests eating poultry, eggs, and sweets only once
a week.
The Latin American food pyramid also advises consumption of
meat, sweets, and eggs only once a week. Like the Asian diet, it
encourages eating fish and shellfish on a daily basis, and unlike the
Mediterranean and Asian diets, it advises consumption of poultry on
a daily basis. As in the other food pyramids, fruit, vegetables, beans,
and whole grains are to be consumed every day. Physical exercise and
water consumption are also emphasized by all three food pyramids.
The Mediterranean Diet Pyramid
The Latin American Diet Pyramid
Source: © 2009 Oldways Preservation & Exchange Trust. www.oldwayspt.org
Source: © 2009 Oldways Preservation & Exchange Trust. www.oldwayspt.org
The Asian Diet Pyramid
Source: © 2000 Oldways Preservation & Exchange Trust. www.oldwayspt.org
134
Understanding Your Health
pay29753_ch05_113-149.indd 134
24/11/11 9:26 AM
Confirming Pages
Table 5.4 DASH Eating Plan
Servings/day
Food Groups
Grains*
Vegetables
Fruits
Dairy
Lean meats, poultry, and fish
Nuts, seeds, and legumes
Fats and oils
Sweets and added sugars
1,600 calories/day
6
3–4
4
2–3
3–6
3/week
2
Less than 3
2,000 calories/day
6–8
4–5
4–5
2–3
6
4–5
2–3
Less than 5
2,600 calories/day
3,100 calories/day
10–11
5–6
5–6
3
6
1
3
Less than 2
12–13
6
6
3–4
6–9
1
4
Less than 2
*Whole grains are recommended for most grain servings as a good source of fiber and nutrients.
Source: National Heart, Lung, and Blood Institute, Your guide to lowering your blood pressure with DASH, 2006, www.nhlbi.nih.gov/health/public/heart/hbp/dash/
how-make-dash.html.
help with the absorption of the iron.33 In addition, vegetarians tend to g et enough calcium from dairy foods,
tofu, beans, soybeans, calcium-fortified cereals, and vegetables such a s broccoli. There has been some concern
about a vitamin B12 deficiency because animal foods are
the best source for B12 and plant foods don’t naturally
contain this vitamin. However, soy foods may contain
vitamin B12, although it is not as biologically active as in
animal foods. Many soy products are fortified with vitamin B12 as well. Note also that the liver stores so much
B12 that it would take years to become deficient in this
vitamin.33 Vegetarians tend to e at healthier diets; have
lower rates of cardiovascular disease, lower blood pressure, lower levels of LDL cholesterol, and less incidence
of diabetes; and weigh 15 percent less than do those who
eat meat. Vegetarian diets encompass a continuum from
diets that allow some animal sources of nutrients to those
that exclude all animal sources. We briefly describe three
vegetarian diets, beginning with the least restrictive in
terms of food sources.
Ovolactovegetarian Diet Depending on the particular
pattern of consuming eggs (ovo) and milk (lacto) or using
one but not the other, ovolactovegetarianism can be an
extremely sound approach to healthful eating during the
entire course of the adult years. An ovolactovegetarian
diet provides the body with the essential amino acids
while limiting the high intake of fats seen in more conventional diets. The exclusion of meat as a protein source
lowers the total fat intake, while the consumption of milk
or eggs allows for an adequate amount of saturated fat to
remain in the diet. The use of vegetable products as the
primary source of nutrients is consistent with the current
dietary recommendations for an increase in fruits and
vegetables and an increase in fiber. Most vegetarians in
the United States are ovolactovegetarians.
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 135
Meatlike products composed of textured vegetable
protein are available in supermarkets. Nonmeat bacon
strips, hamburger and chicken patties, and link sausage can be consumed by people who want to restrict
their meat intake but still want a meatlike product.
Soybeans are a p rimary source of this textured vegetable protein.
Vegetarians who do co nsume dairy products face
challenges when making food choices if they wish to
avoid other animal products in their food. Because most
cheese is made with rennet, a coagulating agent that usually comes from the stomachs of slaughtered newborn
calves, many vegetarians eliminate cheese from their
diet or opt for rennetless cheese. Vegetarian cheeses are
manufactured using rennet from either fungal or bacterial sources. Similarly, yogurt is often made with gelatin
derived from animal ligaments, skins, tendon, and bones
(gelatin is also found in marshmallows, candy such a s
jelly beans and candy corn, poptarts, and a v ariety of
other foods).
It has become easier to follow a vegetarian diet since
stores have begun offering organic vegetarian items that
do not contain these animal products. However, it can be
difficult to avoid all animal products without being an
avid and knowledgeable label reader.
Lactovegetarian and Ovovegetarian Diets People
who include dairy products in their diet but no other
Key Terms
ovolactovegetarian diet (oh voe lack toe veg a ter
ee in) A diet that excludes all meat but does allow the
consumption of eggs and dairy products.
Chapter Five
Understanding Nutrition and Your Diet
135
24/11/11 9:26 AM
Confirming Pages
and breast-feeding women, infants and children, older
adults, and athletes.
Soy foods are an important source of protein and other
nutrients for vegetarians.
animal products, such as eggs and meat, are lactovegetarians. In contrast, people who exclude dairy products such
as milk and cheese, yet consume eggs, are ovovegetarians.
Both diets carry the advantages of ovolactovegetarianism.
Vegan Vegetarian Diet A vegan vegetarian diet is
one in which not only meat but also other animal products, including milk, cheese, and eggs, are excluded.
When compared with the ovolactovegetarian diet, the
vegan diet requires a h igher level of nutritional understanding to avoid nutritional inadequacies.
One potential difficulty is that of obtaining all the
essential amino acids. Since a si ngle plant source does
not contain all the essential amino acids, the vegan must
learn to co nsistently employ a co mplementary diet. By
carefully combining various grains, seeds, and legumes,
amino acid deficiency can be prevented.
In addition to the potential amino acid deficiency,
the vegan could have some difficulty in maintaining the
necessary intake of vitamin B12. Possible ramifications of
inadequate B12 intake include depression, anemia, back
pain, and menstrual irregularity. Vegans often have difficulty maintaining adequate intakes of iron, zinc, and
calcium.1 Calcium intake must be monitored closely by
the vegan. In addition, vitamin D deficiencies can occur.
Supplements and daily exposure to sunshine will aid in
maintaining adequate levels of this vitamin.
A final area of potential difficulty for the vegan is
that of an insufficient caloric intake because of the satiety
resulting from the nature of the diet. Early satiety caused
by a large amount of fiber may lower carbohydrate intake
to the point that protein stores (muscle mass) are used for
energy.
When practiced knowledgeably, vegan vegetarianism is sound for virtually all people, including pregnant
136
Semivegetarian Diets People become vegetarians for
many reasons. Some avoid meat and animal products for
ethical or spiritual reasons. Others choose vegetarianism
for health or environmental reasons. In recent years, however, some people have found a middle ground between
the two eating styles. These so-called semivegetarians ,
also referred to as flexitarians, are increasing their intake
of vegetables and cutting back greatly on meat consumption but not necessarily eliminating meat entirely. Semivegetarians add occasional servings of fish and poultry to
the ovolactovegetarian diet, and some even eat red meat
on occasion. Pesco-vegetarians eat fish, dairy products,
and eggs along with plant foods.
A semivegetarian diet is much healthier than the
typical meat-laden Western diet. The American Cancer Society, the American Heart Association, and the
National Academy of Science all recommend dietary
changes that are closely related to t he typical semivegetarian diet. The health benefits of such a d iet are well
documented.
The semivegetarian diet may be desirable to s ome
people because the limited consumption of meat products may help ward off some nutrient deficiencies, and
such a d iet can be healthier than that of the typical
American.
Nutrition and the Older Adult
Nutritional needs change as adults age. Age-related alterations to the structure and function of the body are primarily responsible for this. Included among the changes that
alter nutritional requirements and practices are changes
in the teeth, salivary glands, taste buds, oral muscles, gastric acid production, and peristaltic action (movement of
food through the gastrointestinal tract). Older adults can
find food less tasteful and harder to chew. Chronic constipation resulting from changes in gastrointestinal tract
function can also decrease interest in eating.34
The progressive lowering of the body’s basal metabolism is another factor that eventually influences dietary
patterns of older adults. As energy requirements fall,
the body gradually senses the need for less food. This
gradual recognition of lower energy needs results in a
lessened food intake and loss of appetite in many older
adults. Because of this decreased need for calories, nutrient density—the nutritional value of a food relative to the
number of calories supplied—is an important factor for
older adults. The USDA dietary guidelines make some
specific suggestions for people over 50. These include
consuming more vitamin B12, because older people tend
to have difficulty absorbing this vitamin. Older adults are
also encouraged to co nsume extra vitamin-D-fortified
foods, since this vitamin may be lacking in this group.
Understanding Your Health
pay29753_ch05_113-149.indd 136
24/11/11 9:26 AM
Confirming Pages
Besides the physiological factors that influence
dietary patterns among the elderly, several psychosocial
factors alter the role of food in the lives of many older
adults. Social isolation, depression, chronic alcohol consumption, loss of income, transportation limitations,
and housing restrictions are factors in lifestyle patterns
that can alter the ease and enjoyment associated with the
preparation and consumption of food.
Special Nutrition Concerns:
Challenges and Tools for Consumers
Nutrition Facts
Serving Size 1 Bar (40g)
Amount Per Serving
Check Calories
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 137
Calories from Fat 60
% Daily Value*
11%
Total Fat 7g
15%
Saturated Fat 7g
Trans Fat 0g
Limit These
Nutrients
Food Labels
Since 1973, food manufacturers have been required by
the FDA to p rovide nutritional information (labels) on
products to which one or more nutrients have been added
or for which some nutritional claim has been made.
Despite the presence of these labels, there was concern
about whether the public could understand the labels as
they appeared and whether additional information was
required. Accordingly, the FDA, in consultation with
individual states and public interest groups, developed
new labeling regulations. Revised labels began appearing on food packages in 1993. The currently used label is
shown in Figure 5-6. Specific types of information contained on the new label are highlighted.
In 2008, the “Country of Origin” legislation took
effect requiring all fresh or frozen meats, fish, fruits,
and vegetables to be identified by their country of origin.
This identification may be made by using a sticker, sign,
placard, or label to indicate the country of the product’s
origin. However, cooked and processed foods, such as
frozen or cooked shrimp and smoked ham or fish, are
exempt. Also exempt are foods packaged together such as
frozen peas and carrots.
As of January 2006, food makers are required by the
FDA to put the amount of trans fat on food labels. The
FDA has further recommended that food labels list calories in larger print, list the percentage of the consumer’s
daily allotment of calories, and list the total amount of
calories in the container, not just the calories per serving. For example, pretzels might be listed as having 100
calories per serving and approximately 15 servings per
bag, leaving it up to you to compute how many servings
and calories you have consumed. The FDA prohibits any
nutrient claim that it has not defined. For example, the
FDA redefines low-fat as containing 3 g rams or less of
fat per serving. The FDA has not yet defined what can be
considered to be low-carb even though many food makers and restaurants use this term in their advertising.
Consumers need to know what is meant by claims such
as low-calorie, low-fat, and low-carb; having a st andard
definition makes it much easier to ma ke healthy and
informed nutritional choices.
Calories 170
Cholesterol 0mg
0%
Sodium 160mg
7%
Total Carbohydrate 24g
8%
Dietary Fiber 3g
12%
Sugars 10g
Protein 5g
Get Enough of
These Nutrients
Vitamin A 2%
Vitamin C 2%
Calcium 20%
Iron 8%
* Percent Daily Values are based on a 2,000 calorie diet.
Your daily values may be higher or lower depending on
your calorie needs:
Calories: 2,000
2,500
Footnote
Total Fat
Less than 65g
Sat Fat
Less than 20g
Cholesterol
Less than 300mg
Sodium
Less than 2,400mg
Total Carbohydrate
300g
Dietary Fiber
25g
Calories per gram:
Fat 9 • Carbohydrate 4 • Protein 4
80g
25g
300mg
2,400mg
375g
25g
Ingredients
Granola Bar (Brown Rice Syrup, Granola [rolled oats, honey, canola oil],
Dry Roasted Peanuts, Soy Crisps [soy protein isolate, rice flour, malt
extract, calcium carbonate], Crisp Brown Rice [organic brown rice flour,
evaporated cane juice, molasses, rice bran extract, sea salt], Glycerine,
Peanut Butter [ground dry roasted peanuts], Inulin, Whey Protein
Isolate, Gold Flax Seeds, Quinoa Flakes, Calcium Carbonate, Salt,
Natural Flavors, Water, Soy Lecithin [an emulsifier]), Dark Compound
Coating (evaporated cane juice, palm kernel oil, cocoa [processed with
alkali], palm oil, soy lecithin [an emulsifier]).
Figure 5-6 The Nutrition Facts Label and Ingredients
List of a Granola Bar
Source: Dietary Guideness for Americans, 2010.
Key Terms
vegan vegetarian diet (vee gun or vay gun) A vegetarian
diet that excludes the consumption of all animal products,
including eggs and dairy products.
semivegetarian diet A diet that significantly reduces but
does not eliminate meat consumption and allows consumption
of dairy products and eggs; also called flexitarian.
pesco-vegetarian diet A vegetarian diet that includes fish,
dairy products, and eggs along with plant foods.
Chapter Five
Understanding Nutrition and Your Diet
137
24/11/11 9:26 AM
Confirming Pages
At the same time, the FDA began requiring food
labels to clearly state if food products contain any proteins derived from any of the eight major food allergens.
In addition, the Food Allergen Labeling and Consumer
Protection Act of 2004 (FALCPA) requires manufacturers to cl early identify the presence of ingredients that
contain protein derived from milk, eggs, fish, crustacean
shellfish, tree nuts, peanuts, wheat, or soybeans in the
list of ingredients or to say “contains” followed by name
of the food allergen after or adjacent to the list of ingredients. However, the FDA does not require manufacturers to p rovide precautionary statements such a s “This
product has been made on equipment that manufactures
peanut products,” and cross-contamination can cause an
allergic reaction. This is very important for those who
suffer from food allergies, and there is a discussion of
this topic later in the chapter.
Anticipating that the FDA would eventually develop
a system to indicate healthy food choices on packaging,
some companies, such a s PepsiCo, General Mills, and
Kellogg, implemented voluntary food labeling using a
green check mark on the front of the item to i ndicate a
“smart choice.” However, this type of labeling came under
fire as high-sugar foods such as Froot Loops and Cracker
Jacks had t hese green “smart choice” check marks on
their packages. Critics claimed that this labeling practice
was more misleading than helpful, as it resulted in people
not reading the nutritional information, assuming that
the food was a h ealthy choice. Consumers may have
believed that these food labels were regulated by the FDA
when in reality they were not. The “smart choice” check
marks are now being replaced by “nutrition keys” on the
front of packages, listing calories, saturated fat, sodium,
and sugars per serving. Again, this is a voluntary nutrition labeling system created by the Grocery Manufacturers’ Association and the Food Marketing Institute, not
the FDA.
A new law, part of the U.S. health care bill, mandates that nutrition information be posted on the menu
or menu board next to the menu item in any restaurant
that has 20 or more locations. This law also applies to
vending machine food. New York City, California, and
Seattle already have this calorie-posting law. The hope is
that Americans will make more informed choices when
eating out. As of 2012, the FDA requires nutrition labels
on beef, poultry, lamb, and pork; previously, this was not
required. The labels list calories, calories from fat, saturated fat, cholesterol, sodium, protein, and vitamins.34
calories from fat), 40–70 percent of the calories in fast
foods are obtained from fats. The restaurant and fastfood industry has received strong criticism for its contribution to creating overweight Americans.
Many restaurants and fast-food chains have discontinued using trans fat in their food and are offering
“diet menus” featuring foods that are lower in caloric
content, fat, and sugar. Subway has a “ fresh-fit,” low-fat
menu; Taco Bell offers items with 9 or fewer grams of fat,
all under 200 calories; Starbucks has under-400-calorie
Panini sandwiches and skinny lattes; and IHOP has
“simple and fit” under-600-calorie menu items.
Despite these efforts, a r ecent study showed that
those who said they ate out at fast-food restaurants at
least twice a w eek gained 10 pounds more than those
who did not. Another study showed that most people
underestimate how many calories they have eaten when
they eat fast food, often by as much as 681 calories. This
makes some sense given that a study of restaurants found
that menu items were up to 18 percent higher in calories
than was listed in the nutritional information. Nutritional information for restaurants and fast-food chains
can be found on websites such as www.chowbaby.com.
While fast-food restaurants are offering some healthy
choices, they still have high-fat, high-calories options
such as Hardee’s Western Bacon Thickburger, weighing
in at 900 calories, 470 from fat; Burger King’s XT Steakburger at 970 calories, 549 from fat; and McDonald’s
Double Quarter Pounder with Cheese at 730 calories,
360 from fat, as well as supersize fries at 610 calories, 261
from fat, and 32-ounce chocolate shake at 770 calories,
160 from fat, for a grand total of 2,110 calories.
Who are these restaurants appealing to w ith these
menu items? Research shows that men ages 18–24 make
fast-food choices based on getting the most for the least
amount of money, not on nutritional value. And don’t be
fooled by thinking that if it’s salad, it’s healthy; that can
be far from the truth. Wendy’s Baja Salad has 740 calories, 420 from fat, and 1,990 mg of sodium. McDonald’s
Southwest Salad with Crispy Chicken, without salad
dressing, has 430 calories, 20 grams of fat, and 920 mg
of sodium.
On the other side of the coin, some healthy fastfood choices are Taco Bell’s Chicken Soft Taco with 150
calories, Wendy’s Grilled Chicken Go Wrap with 127
calories, McDonald’s Hamburger with 250 calories, and
McDonald’s Fruit and Yogurt Parfait with 160 calories.
See the box “Eating on the Run” for more suggestions on healthier fast-food choices.
Fast Foods
Fast foods are convenience foods usually prepared in
walk-in or drive-through restaurants. The nutritional values of fast foods can vary considerably, and fat density
remains a serious limitation of fast foods. In comparison
to the recommended standard (20–35 percent of total
138
TALKING POINTS Which fast-food restaurants
are your favorites? Are you surprised at any of
the information in this chapter regarding your
favorite meals? Will you change your order next time you
visit a fast-food restaurant?
Understanding Your Health
pay29753_ch05_113-149.indd 138
24/11/11 9:26 AM
Confirming Pages
Changing for the Better
Eating on the Run
I am always in a hurry and don’t have time to cook, and so a lot
of my meals end up being fast food. Are there better choices I
can make when eating on the run?
The typical American eats about three hamburgers and four orders of
French fries each week, so you aren’t alone. With over 300,000 fastfood restaurants in the United States, fast food is definitely part of
the American lifestyle. Here are some things to consider when eating
at fast-food restaurants:
• Don’t supersize! Go for the “small” or “regular” size.
• Don’t wait until you are starving because that leads to overeating
and supersizing!
• Decide what you want to order ahead of time, and don’t be
swayed by “value meal” or what “looks good.”
• Ask for a nutritional guide for the menu. Look at the calories, fat
grams, and sodium when making your selection.
Functional Foods
At the forefront of healthful nutrition is the identification
and development of foods intended to affect a particular
health problem or to improve the functional capability of
the body. Functionalfoods contain not only recognized
nutrients but also new or enhanced elements that impart
medicinelike properties to t he food. Alternative labels
also exist for various subclasses of functional foods, such
as nutraceutics, or food elements that may be packaged in
forms appearing more like medications (for example, pills
or capsules), and probiotics.35 Probiotics, “for life,” are
living bacteria (“good bugs”) that are thought to help prevent disease and boost the immune system. Probiotic bacteria have been associated with the alleviation of allergies,
irritable bowel, and respiratory and urinary tract infections, and with cancer prevention. They make the environment in the digestive system inhospitable for harmful
bacteria (the “bad bugs”). More than 400 types of bacteria
reside in and on our bodies and outnumber human cells
10 to 1. Yogurt is one example of a food that gives you a
dose of these good bugs—Lactobacillus bulgaricus.
Examples of functional foods include garlic (believed
to lower cholesterol), olive oil (thought to prevent heart
disease), foods high in fiber (which prevent constipation and lower cholesterol), and foods rich in calcium
(which help prevent osteoporosis). In addition, foods that
contain high levels of vitamins A, C, and E—primarily
fruits and vegetables—and provide the body with natural
sources of antioxidants are functional foods.
Other functional foods are those that contain or are
enriched with folic acid. These vitamin-B-family foods
aid in the prevention of spina bifida and other neural
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 139
• Order grilled instead of fried chicken or fish.
• Look for the “light” choices.
• Limit your condiments. Mustard, ketchup, salsa, and low-fat or
fat-free condiments and dressings are preferable to regular mayonnaise or high-fat dressings.
• Bring fast food from home! Buy portable foods at the grocery
store to take with you that can be eaten quickly and easily, such
as portable yogurt, bananas, apples, low-fat granola bars, or
breakfast bars.
• Order low-fat or skim milk or water instead of soda.
• Go to a variety of different kinds of fast-food restaurants so you
aren’t eating hamburgers every day, and set a limit on how many
meals you are going to eat out each week.
tube defects (see Chapter 12) and the prevention of heart
disease. Foods that are rich in selenium are sometimes
categorized as functional foods because of selenium’s
potential as an agent in cancer prevention. The FDA
approved a “heart healthy” label for foods that are rich
in soy protein,36 although there is some debate about the
impact soy protein has in the prevention of cardiovascular disease. All the functional foods discussed here are
approved to carry health claims on the basis of current FDA criteria.37 Phytosterols are another example of
a functional food. Phytosterols are found in plants and
help lower cholesterol levels. They can be found in oils,
nuts, vegetables, fruits, and legumes.
One category of functional foods being researched
is vegetables that are genetically engineered to p roduce
a specific biological element that is important to human
health. An example is tomatoes that are high in lycopene.
Key Terms
fat density The percentage of a food’s total calories that are
derived from fat; above 30 percent reflects high fat density.
functional foods Foods capable of contributing to the
improvement/prevention of specific health problems.
probiotics Living bacteria (“good bugs”) that help prevent
disease and strengthen the immune system.
health claims Statements authorized by the FDA as having
scientific proof of claims that a food, nutrient, or dietary
supplement has an effect on a health-related condition.
Chapter Five
Understanding Nutrition and Your Diet
139
24/11/11 9:26 AM
Confirming Pages
Food technologists are interested in expanding the functional food family to i nclude a g reater array of healthenhancing food items.
Dietary Supplements
Americans spend $23 billion annually on a wide array of
over-the-counter (OTC) products known collectively as
dietary supplements. These unregulated, nonprescription
products are legally described as
●
●
●
●
Products (other than tobacco) that are intended to
supplement the diet, including vitamins, amino
acids, minerals, glandular extracts, herbs, and other
plant products such as fungi
Products that are intended for use by people to supplement the total daily intake of nutrients in the diet
Products that are intended to be ingested in tablet,
capsule, soft gel, gelcap, and liquid form
Products that are not in themselves to be used as
conventional foods or as the only items of a meal
or diet
Unlike prescription medications, dietary supplements have been available in the marketplace for years
almost without regulation. However, dietary supplements
now must be deemed safe for human use on the basis of
information supplied to t he FDA by the manufacturers.
In addition, the labels on these products cannot make
a direct claim, with the exception of calcium and folic
acid supplements, that they can cure, treat, or prevent illnesses. However, other materials with such cla ims may
be displayed close to the dietary supplements themselves.
Further, the labels on dietary supplements must remind
consumers that the FDA doesn’t have the authority to do
the rigorous research required of prescription medications, and so the FDA cannot attest to their purity, quality, safety, or effectiveness. Beyond this, consumers are
left to themselves to decide whether to purchase and use
dietary supplements (see the box “Should You Take a
Dietary Supplement?”).
As we mentioned, probiotic products, dietary supplements with live bacteria, are gaining in popularity,
with total sales of $1.1 billion. Actimel is one of the biggest sellers, claiming to “help to strengthen your body’s
natural defenses” and enhance your immune system.38
Easily accessible to anyone, over 15,000 different
dietary supplements can be purchased in grocery stores,
drugstores, and discount stores; through mail-order catalogs; and on the Internet. Because of the great demand
for these products, major pharmaceutical companies are
now entering the dietary supplement field. Whether this
trend leads to the development of more effective products,
or to a g reater effort on the part of the FDA to demand
proof of effectiveness, remains to be seen. By definition,
supplements are not foods but simply “supplements.”
140
Therefore, they remain free from requirements to substantiate their claims of effectiveness (as is now required
for functional foods).
TALKING POINTS A friend asks you about the
advantages and disadvantages of taking a
dietary supplement. What would you point
out to your friend?
Food Allergies
Foods enjoyed by the vast majority of people may be
harmful and even deadly to others because of their unique
food allergies. For some people, peanuts, the familiar
snacks still served on many plane flights, are such a food.
Today, U.S. airlines are replacing peanuts with pretzels
in order to p rovide “peanut-free” flights and to p rotect
people known to be allergic to peanuts and peanut-based
products. Many schools have already established peanutfree lunchrooms for the same purpose.
Being intolerant to c ertain foods is not the same
as being allergic to particular foods. Food intolerance
means that a food upsets your intestines, usually because
of an enzyme deficiency. A lactase deficiency, for example, causes lactose intolerance. Lactose intolerance affects
20 percent of Caucasian Americans, 75 percent of Native
Americans and African Americans, 90 percent of Asian
Americans, and 50 percent of Hispanic Americans. Intolerance to gluten (found in wheat, rye, barley, and perhaps
oats) affects 1 o f every 150 Americans and can cause
malnutrition, premature osteoporosis, colon cancer, thyroid disease, diabetes, arthritis, miscarriage, and birth
defects. The incidence of celiac disease has quadrupled;
when someone with this autoimmune disease consumes
gluten, an allergic reaction results.
A food allergy mistakenly calls the body’s diseasefighting immune system into action, creating unpleasant and sometimes life-threatening symptoms. Peanuts,
milk, eggs, shellfish, tree nuts, fish, soy, and wheat
account for 90 percent of food allergies. Food allergies in
American children have increased 18 percent in the past
few years, with African American and Caucasian children having more food allergies than Hispanic children
have. Eight percent of children and 2 p ercent of adults
Key Terms
food intolerance An adverse reaction to a specific food that
does not involve the immune system; usually caused by an
enzyme deficiency.
food allergy A reaction in which the immune system attacks
an otherwise harmless food or ingredient; allergic reactions
can range from mildly unpleasant to life threatening.
Understanding Your Health
pay29753_ch05_113-149.indd 140
24/11/11 9:26 AM
Confirming Pages
Should You Take a Dietary Supplement?
S
Halff off Americans take a dietary supplement
for health, weight management, and athletic
performance enhancement, spending, $23 billion on them in 2009. But what are the risks?
Dietary supplements do not have to have clinical trials to prove their safety or effectiveness
and are not subject to regulation by the FDA.
Due to the lack of quality control, supplements
have been routinely found to contain metals,
pesticides, high amounts of selenium and
chromium, and prescription drugs. People
have reported problems with breathing, liver
failure, kidney failure, stroke, high blood pressure, heart attacks, joint pain, diarrhea, hair
loss, finger-and toenails falling off, skin turning blue, whites of eyes turning yellow, and
fatigue. Fatalities have been associated with
taking dietary supplements as well.
Consumer Reports, along with the Natural
Medicines Comprehensive Database, developed a list of the 12 most dangerous supplements, ones they say should be avoided due
to lack of safety and to adverse side effects.
These include aconite, bitter orange, chaparral, collonoidal silver, coltsfood, comfrey,
country mallow, germanium, greater celadine,
kava, lobelia, and yohimbe. They have been
associated with liver damage, kidney damage,
heart failure, cancer, respiratory problems,
and death.
If you do take a dietary supplement, be
a cautious and informed consumer. Look for
the “USP Verified” mark on the product indicating that the manufacturer has voluntarily
undergone quality control testing by U.S.
Pharmacopeia. USP is a nonprofit, private
have food allergies. Food-based allergies may be serious
or even life threatening.
Because food allergies generally develop slowly, initial
symptoms may not be fully recognized or even associated
with the food. It takes three exposures to the allergic food
to obtain a significant food allergy reaction. The first time
a person eats a food she is allergic to, she may have little
or no reaction. The second time she eats this food, she
will most likely have a more observable reaction, such as
breaking out in hives, itching, having a runny nose, feeling a burning sensation in the mouth, and wheezing. The
third exposure can bring on a full-blown reaction, which,
for peanut allergies among others, can result in death
within minutes. Also, food allergies may develop later in
life. There is no cure for food allergies, and the treatment
is for the food-allergic person to a void these foods and
carry an EpiPen (epinephrine) at all times.
For the first time, an experimental drug has proven
highly effective against potentially deadly peanut allergies. The once-a-month shots don’t cure peanut allergy,
which affects about 1.5 million Americans and kills
50–100 people each year. Xolair, a d rug currently patented for patients with asthma, may hold promise in
preventing or reducing the severity of reactions for people who suffer from peanut allergy. Xolair, an anti-IgE
therapy, blocks a protein called immunoglobulin E from
causing an asthmatic reaction. Genentech and Novartis
Pharmaceuticals are currently conducting clinical trials for use with people who suffer from peanut allergy
in hope that anti-IgE therapy can be used to diminish
or eliminate the reaction caused by peanut allergy in the
same way it treats asthma. However, Xolair is not a cure
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 141
standard-setting authority that verifies the
quality, purity, and potency of the product.
You can check out a list of verified products at www.uspverified.org. If the promises
seem too good to be true, they probably are.
It is illegal for dietary supplement companies
to claim that their product can prevent, treat,
or cure any disease other than ones caused
by nutrient deficiencies. Be sure to tell your
doctor or pharmacist if you are taking any
dietary supplements to avoid negative interactions with prescription medications. If you
experience any problems, consult your doctor
immediately.
Source: Dangerous supplements, Consumer
Reports, September 2010.
or a vaccine. It adds protection against a fatal reaction in
case of accidental ingestion of peanut-containing food.
Scientists also are working on treatments that could suppress peanut allergy permanently, but those developments are probably 5–10 years in the future.
Food Safety
Technological advances in food manufacturing and processing have done much to ensure that the food we eat
is fresh and safe. Yet concern is growing that certain
recent developments may also produce harmful effects
on humans. For example, the preparation, handling, and
storage of food; irradiation of foods; and genetic engineering of foods all contribute to the safety of our food.
Preventing Foodborne Illness
Foodborne illness or food poisoning is the result of eating contaminated food. The symptoms of food poisoning
can be easily mistaken for the flu—fatigue, chills, mild
fever, dizziness, headaches, upset stomach, diarrhea, and
cramps. Illness develops within one to six hours following
ingestion of the contaminated food, and recovery is fairly
rapid.39 However, new research suggests that 10 percent
of people who contract food poisoning from ingesting
food with Escherichia coli develop a life-threatening illness, hemolytic uremic syndrome, which can cause kidneys and other major organs to e ventually fail. Bacteria
are the culprits in most cases of food poisoning, which
can be the result of food not being cooked thoroughly to
Chapter Five
Understanding Nutrition and Your Diet
141
24/11/11 9:26 AM
Confirming Pages
destroy bacteria or not being kept cool enough to slow
their growth. In addition, nearly half of all cases of food
poisoning can be prevented with proper hand washing so
as to not contaminate food with viruses, parasites, or toxic
chemicals. Food safety is such an important issue that the
USDA incorporated it into the current dietary guidelines.
Food should be refrigerated below 408F or kept warm
above 1408F. Between 408F and 1408F, bacteria can double
in number in as little as 20 minutes, so it is important to
keep food at safe temperatures. See Figure 5-7 on temperature rules for safe cooking and handling of foods.
It is estimated that 1 of every 4 Americans is the victim of food poisoning each year, and about 5,000 of these
people die. Salmonella bacteria are the most common
cause of foodborne illness and are found mostly in raw
or undercooked poultry, meat, eggs, fish, peanut butter,
fruit, vegetables, unpasteurized milk, and even pet food.
Clostridium perfringens, also called the “buffet germ,”
grows where there is little to no oxygen and grows fastest in large portions held at low or room temperatures.
For this reason, buffet table servings should be replaced
often and leftovers should be refrigerated quickly. Refrigerated leftovers may become harmful to e at after three
days (see Table 5.5). The old adage “If in doubt, throw it
out” applies to any questionable leftovers. A third type of
food poisoning is botulism, which is rare but often fatal.
Table 5.5 Cold Storage Limits
Apples
Apricots, peaches, nectarines, pears
Bacon
Beans, green
Berries, cherries
Butter
Carrots
Cheese, hard
Cheese, soft
Chicken or turkey (fresh)
Chicken or turkey (cooked)
Citrus fruit
Deli and vacuum-packed products
Eggs (fresh, in shell)
Eggs (hard cooked)
Fish or seafood (fresh)
Fish (cooked)
Fish (canned, after opening)
Gravy and meat broth
Hot dogs (after opening)
Lettuce, leaf
Luncheon meat (after opening)
Margarine
Mayonnaise (after opening)
Milk (after opening)
Meat (fresh, ground)
Meat (fresh; steak, chops, roasts)
Meat (cooked)
Pizza (cooked)
Soups and stews
Spinach
Yogurt
3 weeks
3–4 days
1 week
3–4 days
1–2 days
1–3 months
2 weeks
3–4 weeks
1 week
1–2 days
3–4 days
1–2 weeks
3–5 days
3–5 weeks
1 week
1–2 days
3–4 days
3–4 days
1–2 days
1 week
3–7 days
3–5 days
4–5 months
2 months
5 days
1–2 days
3–5 days
3–4 days
3–4 days
3–4 days
1–2 days
7–14 days
Sources: Food Safety and Inspection Service, U.S. Department of Agriculture,
Basics for Handling Food Safely, September 2010; Food Marketing Institute,
A Consumer Guide to Food Quality and Safe Handling.
165°F
Poultry breasts, turkey, stuffing,
ground poultry, reheated leftovers
160°F
Meats (medium), egg dishes, pork,
and ground meats
145°F
Fish
140°F
Hold hot foods
DANGER ZONE
40°F
Refrigerator temperature
0°F
Freezer temperature
Figure 5-7 Temperature Rules for Cooking and Safe Handling of
Food Keep food out of the danger zone between 40°F and 140°F,
in which bacteria can multiply rapidly.
Source: U.S. Department of Health and Human Services and U.S. Department
of Agriculture, Dietary Guidelines for Americans, 2010, www.healthierus.gov/
dietaryguidelines.
142
It is caused by home-canned or commercially canned
food that hasn’t been processed or stored properly. Some
warning signs are swollen or dented cans or lids, cracked
jars, loose lids, and clear liquids turned milky. Can you
tell if meat is spoiled by looking at it? Not necessarily. Some supermarkets package their meat with carbon
monoxide, which reacts with the pigment in the meat to
make it redder.
The Center for Science in the Public Interest found
that fruits and vegetables account for the majority of
foodborne illnesses. Salads are by far the biggest culprit.
The reason for this seems to be because some of the water
used to irrigate and wash produce is contaminated with
human and animal feces. Escherichia coli has historically been a harmless bacterium that resides in the guts
of animals, including humans. A n ew and pathogenic
strain called E. coli O157:H7 was identified in 1982 and
now causes an estimated 73,000 cases of infection and
60 deaths in the United States each year. E. coli can be
found in uncooked produce, raw milk, unpasteurized
juice, contaminated water, and meat. Dozens of people
Understanding Your Health
pay29753_ch05_113-149.indd 142
24/11/11 9:26 AM
Rev. Confirming Pages
contracted food poisoning from the green onions in food
served at some Taco Bell restaurants in 2006. This same
strain of E. coli was linked to t he spinach that sickened
200 people in 2006. In 2009, over 600 people in 43 states
were sickened by tainted peanut butter produced by the
Peanut Corp of America (PCA). Twenty-three percent of
these people were hospitalized and at least nine died as a
result of salmonella poisoning. In its report on the PCA,
the FDA found poor sanitation in the form of bird feces,
tainted water, and cockroaches accounted for the salmonella. In addition, the FDA contended that there were
substandard food inspections, so that the problem was
not discovered and corrected quickly. In fact, the FDA
issued a recall of the company’s products from the previous two years, involving over 432 different products such
as crackers, cookies, and ice cream.
A salmonella outbreak caused by eggs from infected
hens occurred in 2010. Over 1,500 people became ill, and
550 million eggs from two facilities were recalled. Salmonella was found in chicken feed. A new FDA egg safety
rule took effect later that year requiring new procedures
for salmonella enteritidis testing and pasteurization.
Another new food safety bill passed requiring that manufacturers alert government officials within 24 hours of
knowledge of contaminated products, calling for more
frequent inspections for food production facilities, giving regulators more power to recall products and suspend or shut down plants with poor safety records, and
strengthening surveillance to track foodborne illnesses.40
Because produce comes from all over the world,
this bacteria problem can be difficult to regulate or correct. Even the ready-to-eat bags of produce that boast
they have been ªthoroughlyº or ªtriple” washed cannot
be guaranteed to be bacteria-free. Washing the produce
yourself may not solve the problem, either. Produce
washes such as veggie wash don’t claim to kill E. coli, but
only to clean off wax, pesticides, and dirt. The best way
to avoid getting sick from produce is to cook it so that
you kill any remaining bacteria.
What do you do if you suspect food poisoning?
●
●
●
Contact a medical professional immediately. D on’t
wait to see if you feel better.
Report the incident to your local health department
as soon as possible if the suspected food came from a
public place.
Preserve the suspected food including any packaging
to give to the health department for investigation
and possible prevention of further poisoning.
Handle food properly to avoid food poisoning. Frequent handwashing is at the top of the list of food safety
tips (see the box ªDos and Don’ts for Food Safetyº). Bacteria live and multiply on warm, moist hands, and hands
can inadvertently transport germs from one surface to
another. It is also important to clean work surfaces with
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 143
Dos and Don’ts for
Food Safety
Do . . .
1. Wash your hands.
2. Put groceries away as soon as you get home and don’t make
other stops first.
3. Use two different plates for raw and grilled meat.
4. Use different spoons to stir and taste the food, and use each
tasting spoon only once.
5. Refrigerate leftovers from restaurants immediately.
6. Use different knives to cut raw meat and chop vegetables.
7. Store food in an airtight container. Don’t store food in open
cans or on uncovered dishes.
8. Wash fresh fruits and vegetables, even if you are throwing
away the rind or peels, because cutting through the produce
can carry bacteria from the outside surface to the inside of
the produce.
Don’t . . .
1. Rinse poultry or meat in water, because this can cause
cross-contamination.
2. Thaw food on the countertop—keep it in a covered container
in the refrigerator.
3. Leave food out of the refrigerator for too long.
4. Use wooden cutting boards with deep grooves or knife scars.
5. Marinate food at room temperature.
Source: Adapted from The American Dietetic Association’s Monthly Nutrition
Companion: 31 Days to a Healthier Lifestyle, by R. Duyff, Chronimed Publishing, 1997. Copyright © 1997 American Dietetic Association. Reproduced with
permission of John Wiley & Sons, Inc. and the Leap First Literary Agency.
hot, soapy water and keep nonfood items such a s the
mail, newspapers, and purses off the countertops. Some
people advocate the use of antibacterial products; others
maintain that if they are overused, these products can
lose their effectiveness, and bacteria then become resistant to them. Utensils, dishes, cutting boards, cookware,
and towels and sponges need to be washed in hot, soapy
water and rinsed well.41
Food Irradiation
Because of the increasing concern about contaminated
meat and meat products, the first irradiated meat, ground
beef, arrived in American supermarkets in early 2000.
Irradiated frozen chicken was introduced more recently.
Irradiation is a process that causes damage to t he DNA
of disease-causing bacteria such a s salmonella and E.
coli as well as of insects, parasites, and other organisms
so that they can’t reproduce. While irradiated meat
has much lower bacteria levels than regular meat does,
irradiation doesn’t destroy all bacteria in meat. In fact,
Chapter Five
Understanding Nutrition and Your Diet
143
11/30/11 4:43 PM
Confirming Pages
irradiation actually destroys fewer bacteria than does
proper cooking.42 The FDA also approved irradiation of
spinach and lettuce to kill E. coli and other germs. There
is some concern that irradiation will lull consumers into
a false sense of security so that they erroneously believe
that they don’t have to take the usual precautions in food
handling and preparation. For example, undercooking,
unclean work surfaces or cooking utensils, and improper
storage can still contaminate meat. Some also claim that
irradiated meat has a d istinct off-taste and a sm ell like
“singed hair.”
Safe Farming Techniques
In recent decades, there has been an increased push
toward ensuring better treatment of animals raised for
slaughter and for dairy production in the United States.
As a result of recent reforms, more than half of beef cattle in North America meet their end at slaughterhouses
based on innovative designs that consider the fears and
inclinations of herd animals. The cages of laying hens are
nearly one-third larger than the old ones were, and the
practice of starving hens for weeks at a t ime to stimulate egg production is beginning to be phased out. These
reforms are important to ensure more humane treatment
of these animals, but they are also proving beneficial to
human health and food quality. It has been suggested that
there is an increase in the quality of meat when animals
are treated humanely, with less bruising, more tenderness, lower incidence of dark-cutting beef, and lessened
occurrence of pale, soft, and dry pork. Furthermore, the
taste of eggs is said to be significantly better if they come
from humanely treated hens.
One important component in these reforms—some
of which have been government mandated and others
voluntarily adopted by the agricultural industry—relates
to the feed given to b eef cattle. The spread of bovine
spongiform encephalopathy, more commonly known as
mad cow disease, has largely been attributed to t he use
of animal feed containing the protein-rich by-products of
slaughtered cows, including nerve tissue, the tissue most
likely to harbor the disease. Such feed—which is believed
to be the primary, if not the only, way the disease can
be transmitted—was banned in the United States and
Canada in August 1997.39 However, from August 1997
to March 2004, 52 companies recalled 410 feed products because of suspected infectious prions, the proteins
thought to spread mad cow disease. While the disease had
been restricted to European cows, three cases from 2003
to 2006 of mad cow disease detected in American cattle
encouraged the U.S. government to impose even stricter
rules to protect the nation’s beef supply from the disease,
including banning the butchering of sick or injured cows,
banning certain animal parts from the food supply, and
increasing testing on suspect animals.43
144
Eliminating animal products from feed has also
proven beneficial for hens. Many consumers choose to
eat only poultry and eggs from free-range, vegetarian-fed
chickens, for health and safety reasons. Several companies
(such as Eggland’s Best) claim that their vegetarian-fed
hens produce eggs that have seven times more vitamin
E, are lower in cholesterol, have a h igher unsaturated/
saturated fat ratio, and contain more omega-3 fatty acids
than do factory-farmed eggs.44
There has also been increasing concern about giving
chickens Roxarsone (3-Nitro) because it contains arsenic.
It is given to chickens to fatten the birds faster and to kill
microbes. Human antibiotics are also fed to chickens to
increase growth, but the bacteria in the chickens’ intestines can develop resistance to t he antibiotics. This can
result in the antibiotic-resistant bacteria being passed
along to people who consume this poultry, causing them
to become ill and not respond to drugs typically prescribed to treat this illness.
Organic Foods
The current USDA organic food labels went into effect in
October 2002 to standardize regulations for foods grown
without synthetic pesticides or other chemicals. Under
the current USDA rules, organic means the following:
●
●
●
●
●
Meat, poultry, and eggs are from animals given
no growth hormones or antibiotics. Vitamin and
mineral supplements are allowed. Livestock are
given organic feed and live in conditions that allow
for “exercise, freedom of movement, and reduction
of stress.” Organic milk and meat must come from
livestock that are allowed to graze at least four
months a year.
Products are not genetically engineered or irradiated
to kill germs.
Crops are grown on land that has not been fertilized
with sewage sludge or chemical fertilizers.
Pests and plant diseases are treated primarily with
insect predators, traps, natural repellants, and other
nonchemical methods.
Weeds are controlled by mulching, mowing, hand
weeding, or mechanical cultivation, not chemical
herbicides.
There are different types of organic foods: “100 percent
organic,” meaning the food contains all organic ingredients; “organic,” meaning at least 95 percent of the product is organic; and “made with organic ingredients,”
meaning at least 70 percent of the food is organic as previously defined.45
In recent years, the $24-billion organic food industry has enjoyed a 2 0 percent annual growth rate, much
higher than that of the rest of the food industry. Almost
Understanding Your Health
pay29753_ch05_113-149.indd 144
24/11/11 9:26 AM
Confirming Pages
70 percent of people said they bought organic food at least
once in the past three months. While organic foods have
been found to ha ve fewer pesticides, to do l ess damage
to the environment, and possibly to have more nutrients,
they can still contain some pesticide residue and chemical contaminants from the environment and have risk
of E. coli contamination. See Chapter 20 for more information on the benefit of organic foods for health and
food safety.
Food Additives
Food additives are substances added to food to preserve and improve its taste and appearance. Some additives are thickening agents, and some add co lor and
prevent food from spoiling. Food additives are found
in all types of foods and beverages, such as meat, soup,
salad dressings, peanut butter, chips, cakes, cookies,
and soda. Vinegar, food coloring, artificial sweeteners,
white sugar, salt, monosodium glutamate (MSG), and
antioxidants are some common examples of additives.
For example, emulsifiers help give peanut butter a more
consistent texture and prevent separation, while stabilizers and thickeners give ice cream a sm oother, more
uniform texture. The three most common additives
are sugar, salt, and corn syrup.46 Food additives must
undergo FDA testing and approval to ensure that the
benefits outweigh any risks associated with them. There
has been some debate about how safe some additives are
despite their FDA approval. Some of the ones in question are aspartame (NutraSweet); red, blue, yellow, and
green food coloring; saccharin; propyl gallate; potassium bromate; sodium nitrate; and 2-methylimidazole
(2-MEI) and 4-methylimidazole (4-MEI), the caramel
coloring found in products such as cola drinks, beer, and
soy sauce; and stevia. These additives have been linked
with an increased risk of cancer.
Genetically Modified Foods
Genetically modified foods are crops that are bred with
genes engineered in labs so that they are more resistant to
pests, disease, drought, and cold; produce higher yields;
and have a higher nutritional content. Ten percent of
farm acreage worldwide is planted with genetically engineered or biotech crops, an increase from 1 p ercent 15
years ago. Soybeans, corn, cotton, canola, sugar beets,
alfalfa, papaya, summer squash, and potato are the most
commonly grown genetically engineered crops.47
The success of American agriculture, in terms of
food quality and marketability, has been based on the
ability to genetically alter food sources to improve yield,
reduce production costs, and introduce new food characteristics. Today, however, genetic technology is so sophisticated that changes are being introduced faster than
scientists can fully evaluate their effects. For example,
the genetic makeup of plant seeds and animals is being
modified while scientists are still trying to de termine
whether humans can safely consume these products over
extended periods. Concerned individuals and agencies in
the United States and abroad are calling for more extensive long-term research into safety issues and stricter
labeling requirements for genetically altered foods.48 The
label GM (for genetically modified ) is appearing on some
food items. Some food manufacturers have announced
that they will discontinue the use of genetically modified ingredients in their products. The American public
appears about equally divided in believing that genetically modified foods are safe (44 percent) or unsafe (20
percent) or that they are uncertain (36 percent) about the
safety of such foods.49
In 2008 the FDA finally decided after seven years
of discussion to a llow the commercial use of genetically
engineered animals. The FDA stated that it would allow
animals to b e genetically altered if such a nimals produce drugs, serve as models for human disease, produce
industrial or consumer products, or have improved fooduse qualities such as being more nutritious. Animals are
considered genetically altered when either their genes are
changed or genes from another animal are added for a specific purpose. This regulation is consistent with legislation
concerning giving drugs to animals for similar reasons.48
Key Terms
food additives Chemical compounds intentionally added to
the food supply to change some aspect of the food, such as
color or texture.
genetically modified foods Crops bred with genes engi-
Organic products have grown in popularity in recent years and
are now available in many major grocery stores.
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 145
neered in labs so that the crops are improved, such as being
drought, pest, or cold resistant; producing a higher yield;
and/or having a higher nutritional content.
Chapter Five
Understanding Nutrition and Your Diet
145
24/11/11 9:26 AM
Confirming Pages
Taking Charge of Your Health
T
• Take
T k the
h Personal Assessment “Are You
Feeding Your Feelings?” at the end of this
chapter to determine if you are an emotional eater.
• Look on MyPlate.gov to find your personal
food plate.
• Assess your physical activity level using
MyPlate.gov.
• Keep track of your food intake for a week,
using the tracker on MyPlate.gov, and see
how well your intake reflects the current
dietary guidelines.
• Make one change per week in your eating
patterns, such as drinking skim milk or
including a new fruit or vegetable.
SUMMARY
●
●
●
●
●
●
Carbohydrates are composed of sugar units and are the
major source of energy for the body. About 45–65 percent
of our calories should come from carbohydrates.
Fats provide a concentrated source of energy for the body
and keep us from feeling hungry. No more than 20–35
percent of our calories should come from fats, and most of
these fats should be polyunsaturated or monounsaturated.
Foods containing trans fats should be avoided as much as
possible, and less than 10 percent of our calories should
come from saturated fats, according to the current dietary
guidelines.
Protein primarily promotes growth and maintenance of
body tissue, and is also a source of energy.
Vitamins serve as catalysts for the body and are found in
either water-soluble or fat-soluble forms.
Minerals are incorporated into various tissues of the body
and also participate in regulatory functions within the body.
●
●
●
●
Adequate water and fluids are required by the body on a
daily basis and are obtained from a variety of food sources,
including beverages.
Fast foods should play a limited role in daily food intake
because of their high fat density, as well as their high levels
of sugar and sodium.
Preventive strategies such as hand washing and proper
preparation, cooking, and storage of food can help to
decrease foodborne illnesses.
The USDA Dietary Guidelines for Americans focus on the
role that trans fat, saturated fat, sugar, sodium, and alcohol play in weight management and health and disease.
These guidelines address the importance of daily physical
activity.
REVIEW QUESTIONS
1. What unique contributions do carbohydrates, fats, and
protein each make to overall nutrition?
2. What role do vitamins play in the body? What is the
most current perception regarding the need for vitamin
supplementation?
3. What roles do minerals play in the body? What is a trace
element?
4. What is the current recommendation regarding daily
fluid intake? Why is water considered an essential
nutrient?
5. What are the two principal forms of fiber, and how does
each of them contribute to health?
6. What are functional foods, and what contribution do they
make to health beyond supplying various nutrients as do
all foods?
7. Identify each of the food groups in the MyPlate current
food guidelines. What is the additional group? Explain
the nutritional benefit of each food group and the recommended daily adult allotments. What are discretionary
calories?
8. What are the specific areas of nutritional concern
addressed by the Dietary Guidelines for Americans?
9. What do the dietary guidelines suggest in terms of physical activity, and what are the benefits of such physical
activity?
10. What is the principal concern regarding excessive fastfood consumption? How can food selection at a fast-food
restaurant be made nutritionally healthier?
ANSWERS TO THE “WHAT DO YOU KNOW?” QUIZ
1. True
2. True
3. False
4. False
5. False
.6 True
7. False
Visit the Online Learning Center (www.mhhe.com/payne12e), where you will find tools to help you improve your grade including
practice quizzes, key terms flashcards, audio chapter summaries for your MP3 player, and many other study aids.
146
Understanding Your Health
pay29753_ch05_113-149.indd 146
24/11/11 9:26 AM
Confirming Pages
SOURCE NOTES
1. Wardlaw GM, Byrd-Bredbenner C, Moe G, Beshgetoor D, Berning J.
Perspectives in Nutrition (8th ed.). New York: McGraw-Hill, 2002.
2. Consumers are caught in sugar battle. USA Today, March 2, 2010.
3. USDA Agricultural Outlook. Washington, DC: U.S. Department of
Agriculture, April 2000.
4. Can sugar substitutes make you fat? Time Magazine, February 2008.
5. Lichtenstein AH. Dietary trans fatty acid. Journal of Cardiopulmonary Rehabilitation, 20(3), 143–146, 2000.
6. Willer WC, Ascherio A. Trans fatty acids: are the effects only marginal? American Journal of Public Health, 84, 722, 1994.
7. Duyff R. American Dietetic Association Complete Food and Nutrition
Guide (3rd ed.). Hoboken, NJ: Wiley, 2006.
8. Katan MB. Trans fatty acids and plasma lipoproteins. Nutrition
Review, 58(6), 188–191, 2000.
9. National Institutes of Health. Practical Guide to the Identification,
Evaluation and Treatment of Overweight and Obesity in Adults.
Bethesda, MD: Author, 2001.
10. Cheskin LJ, et al. Gastrointestinal symptoms following consumption
of Olestra or regular triglyceride potato chips score. Journal of the
American Medical Association, 279(2), 150–152, 1998.
11. Wardlaw GM, Smith A. Contemporary Nutrition: Issues and Insights.
New York: McGraw-Hill, 2010.
12. Soy what?Nutrition Action, November 2009.
13. Soyonara: tough times for the miracle bean. Nutrition Action,
October 2006.
14. National Academy of Sciences. Dietary Reference Intakes. Washington, DC: National Acadamies Press, 2004.
15. Czeizel AE, Dudaz I. Prevention of the first occurrence of neuraltube defects by periconceptional vitamin supplementation. New England Journal of Medicine, 327(26), 1832–1835, 1992.
16. Getting enough: what you don’t eat can hurt you. Nutrition Action,
September 2010.
17. Antioxidants: still hazy after all these years. Nutrition Action,
November 2005.
18. www.starbucks.com/menu .
19. Garigan TP, Ristedt DE. Death from hyponatremia as a result of
acute water intoxication in an army basic trainee. Military Medicine,
164(3), 234–238, 1999.
20. Arieff AI, Kronlund BA. Fatal child abuse by forced water intoxication. Pediatrics, 103(6 Pt 1), 1292–1295, 1999.
21. Chandalia M, et al. Beneficial effects of high dietary fiber intake in
patients with type 2 diabetes mellitus. New England Journal of Medicine, 342(19), 1392–1398, 2000.
22. Schatzkin A, et al. Lack of effect of a low-fat, high-fiber diet on the
recurrence of colorectal adenomas. Polyp Prevention Trial Study
Group. New England Journal of Medicine, 342(16), 1149–1215, 2000.
23. Sears W, Sears M. The Family Nutrition Book. New York: Little,
Brown, 1999.
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 147
24. Study: eating more fiber could mean longer life. USA Today,
February 15, 2011.
25. Whole grains linked to lower blood pressure. Bottom Line Health,
25(5), May 2010.
26. The changing American diet. Nutrition Action, April 2006.
27. www.health.gov/dietaryguidelines/dga ,2010.
28. American Cancer Society. Cancer Facts and Figures—2010. The Association, 2010.
29. Marcus E. On the fast track to health. Newsday, January 7, 2004,
p. B14.
30. Flour power: A slice of multigrain can taste like bread. USA Today,
August 9, 2004.
31. Sugar overload. Nutrition Action, January/February 2010.
32. Cook N, Cutler J, Osborzanck E, Buring J, Rexrode K, Kumanyika S,
et al. Long-term effects of dietary sodium reduction on cardiovascular disease outcomes: observational follow-up of trials of hypertension prevention (TOHP). British Medical Journal, 334, 385,
April 2007.
33. Keeping a lid on salt: not so easy. USA Today, April 28, 2010.
34. Debuting in 2012: What’s in the beef? USA Today, December 29,
2010.
35. Some bacteria for brunch? U.S. News & World Report, December 10,
2007.
36. FDA Approves New Health Claim for Soy Protein and Coronary
Heart Disease [FDA talk paper]. U.S. Food and Drug Administration
Center for Food Safety and Applied Nutrition, October 1999.
www.fda.gov/fdac/bbs/topics/ANSWERS/ANSoo980.html .
37. 10 mega-trends in the supermarket. Nutrition Action, May 2003.
38. A bug for what’s bugging you. USA Today, July 9, 2003.
39. Oppel RA, Jr. Infected cow old enough to have eaten now-banned
feed. New York Times, December 30, 2003.
40. Egg crisis piques interest in bill. USA Today, August 25, 2010.
41. Rinzler C. Nutrition for Dummics (4th ed.). Hoboken, NJ: Wiley,
2006.
42. The truth about irradiated meat. Consumer Reports, 34–37, August
2003.
43. Grady D. U.S. imposes stricter safety rules for preventing mad cow
disease. New York Times, December 31, 2003.
44. Corporate website, www.eggland.com .
45. USDA gives bite to organic label. USA Today, October 16, 2002.
46. Insel P, Turner E, Ross D. Nutrition. Sudbury, MA: Jones & Bartlett,
2007.
47. Farmers growing more genetically engineered crops. USA Today,
February 23, 2011.
48. FDA moves on genetically altered animals. USA Today, September 19,
2008.
49. Americans are iffy on genetically modified foods. USA Today,
September 18, 2003.
Chapter Five
Understanding Nutrition and Your Diet
147
24/11/11 9:27 AM
Confirming Pages
Personal Assessment
Rate Your Plate
Take a closer look at yourself, your current food decisions,
and your lifestyle. Think about your typical eating pattern
and food decisions.
Score Yourself
Usually 5 2 points
Sometimes 5 1 point
Never 5 0 points
Do You . . .
Usually
Consider the MyPlate
model when you make
food choices?
Try to eat regular meals
(including breakfast),
rather than skip or skimp
on some?
Choose nutritious snacks?
Try to eat a variety of
foods?
Include new-to-you foods
in meals and snacks?
Try to balance your energy
(calorie) intake with your
physical activity?
Sometimes
Never
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
24 or more points—Healthful eating seems to be your fitness habit already. Still, look for ways to stick to a healthful
eating plan—and to make a “good thing” even better.
16 to 23 points—You’re on track. A few easy changes could
help you make your overall eating plan healthier.
9 to 15 points—Sometimes you eat smart—but not often
enough to be your “fitness best.”
0 to 8 points—For your good health, you’re wise to rethink
your overall eating style. Take it gradually—step by step!
❏
❏
❏
TO CARRY THIS FURTHER . . .
❏
❏
❏
Now for the Details
148
Whatever your score, make moves for healthful eating.
Gradually turn your “nevers” into “sometimes” and your
“sometimes” into “usually.” Try some of the suggestions
from the discussion of MyPlate and the Dietary Guidelines
for Americans.
Source: Adapted from R. Duyff, The American Dietetic Association’s
Monthly Nutrition Companion: 31 Days to a Healthier Lifestyle,
Chronimed Publishing, 2006. Copyright © 2006 American Dietetic
Association. Reproduced with permission of John Wiley & Sons, Inc.
Do You . . .
Consume half of your
grains as whole-grain
products?
Eat at least 2½ cups of
vegetables daily?
Eat at least 2 cups of
fruits daily?
Consume at least 3 cups
of milk, yogurt, or cheese
daily?
Choose low-fat foods?
Choose low-sodium
foods?
Drink 8 or more cups of
fluids daily?
Limit alcoholic beverages
(no more than 1 daily
for a woman or 2 for a
man)?
If you scored . . .
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
❏
Understanding Your Health
pay29753_ch05_113-149.indd 148
24/11/11 9:27 AM
Confirming Pages
Personal Assessment
Are You Feeding Your Feelings?
Sometimes people use food as a way of coping with their
emotions and problems. To identify how you might be
using food as a coping strategy and what feelings you tend
to associate with eating, complete the following inventory.
05 Never
15 Rarely
25 Occasionally
35 Often
45 Always
1. _____ Do you eat when you are angry?
2. _____ When you feel annoyed, do you turn to food?
3. _____ If someone lets you down, do you eat to comfort
yourself?
4. _____ When you are having a bad day, do you notice
that you eat more?
5. _____ Do you eat to cheer yourself up?
6. _____ Do you use food as a way of avoiding tasks you
don’t want to do?
7. _____ Do you view food as your friend when you are
feeling lonely?
8. _____ Is food a way for you to comfort yourself when
your life seems empty?
9. _____ When you are feeling upset, do you turn to food
to calm yourself down?
10. _____ Do you eat more when you are anxious, worried,
or stressed?
11. _____ Does eating help you to cope with feeling
overwhelmed?
12. _____ Do you eat more when you are going through
big changes or transitions in your life?
13. _____ Do you reward yourself with food?
14. _____ When you think you have done something
wrong, do you punish yourself by eating?
15. _____ When you are feeling badly about yourself, do
you eat more?
16. _____ When you feel discouraged about your efforts
to improve yourself, do you eat more, thinking
“What’s the use of trying”?
_____ TOTAL SCORE
www.mhhe.com/payne12e
pay29753_ch05_113-149.indd 149
Interpretation
If your total score is . . .
0 to 16—You don’t eat to cope with your emotions. Your
eating may not be related to your emotional state. However,
you may avoid eating when you are upset or having trouble
coping with your feelings. You may run away from food
rather than running to food to cope.
17 to 47—Although you fall in the average range, you may
use food to deal with specific situations or feelings such as
anger, loneliness, or boredom. See the breakdown of scores
below to identify how you may be using food to cope with
particular feelings.
48 to 64—You run to food to cope with your emotions, and
you may want to consider developing other ways of appropriately expressing your feelings.
Next, look more closely at your specific responses . . .
If you answered “3” or “4” to most of questions 1–4, this
can be indicative of eating when you are angry.
If you answered “3” or “4” to most of questions 5–8, this
can be indicative of eating when you are lonely or bored.
If you answered “3” or “4” to most of questions 9–12, this
can be an indication that you are a stress eater.
If you answered “3” or “4” to most of questions 13–16, this
can be an indication that you are using food to cope with
feelings of low self-esteem and self-worth.
TO CARRY THIS FURTHER . . .
• Use the assessment scores to help you learn to recognize
the triggers for your emotional eating.
• Make a list of things to do when you get the urge to eat
and you’re not hungry. Try going for a walk or calling a
friend to distract yourself.
• Do something fun if you are tempted to eat to avoid
work or a dreaded task.
• Reward yourself with things other than food.
Source: Adapted from Nutrition for Healthy Living. Courtesy of
Marcy Leeds.
Chapter Five
Understanding Nutrition and Your Diet
149
24/11/11 9:27 AM